Athletic Performance

Need to Know

1.	Creatine Monohydrate

About

About This Condition

Aside from training, nutrition may be the most important influence on athletic performance.¹ However, in seeking a competitive edge, athletes are often susceptible to fad diets or supplements that have not been scientifically validated. Nevertheless, there is much useful research to guide the exerciser toward optimum health and performance.

Eating Right

The right diet is the key to managing many diseases and to improving general quality of life. For this condition, scientific research has found benefit in the following healthy eating tips.

Recommendation	Why	Get started
Fuel up	Athletes have different calorie requirements, depending on the intensity of their training and performance. Calorie restriction can have many negative effects, so be sure to get enough fuel through calories.
Fuel up Calorie requirements for athletes depend on the intensity of their training and performance. The athlete who trains to exhaustion on a daily basis needs more fuel than one who performs a milder regimen two or three times per week. Calorie requirements can be as much as 23 to 39 calories per pound of body weight per day for the training athlete who exercises vigorously for several hours per day.² ^{, 3} Many athletes compete in sports having weight categories (such as wrestling and boxing), sports that favor small body size (such as gymnastics and horse racing), or sports that may require a specific socially accepted body shape (such as figure skating). These athletes may feel pressured to restrict calories to extreme degrees to gain a competitive edge.⁴ Excessive calorie restriction can result in chronic fatigue, sleep disturbances, reduced performance, impaired ability for intensive training, and increased vulnerability to injury.⁵
Get enough protein	Athletes require more protein than people who are not exercising vigorously, but supplementing is not necessary as long as the diet contains at least 12 to 15% of calories as protein.
Get enough protein Protein requirements are often higher for both strength and endurance athletes than for people who are not exercising vigorously; however, the increased food intake needed to supply necessary calories and carbohydrates also supplies extra protein. As long as the diet contains at least 12 to 15% of calories as protein, or up to 0.75 grams per day per pound of body weight, protein supplements are neither necessary, nor likely to be of benefit.⁶ ^{, 7} Concerns have been raised that the very high-protein diets sometimes used by body builders could put stress on the kidneys, potentially increasing the risk of kidney disease later in life. A preliminary study of male athletes consuming at least 2.77 grams per pound of body weight per day showed no evidence of kidney impairment; however, the study was limited to one month, and evidence of long-term kidney problems associated with chronic protein loading were not examined.⁸ Preliminary studies have suggested that increased protein intake may have biological effects that could improve muscle growth resulting from strength training, especially if liquid supplements (typically containing at least 6 grams of protein or amino acids in addition to varying amounts of carbohydrate) are taken either immediately after exercise or just before exercise.⁹ ^{, 10} ^{, 11} ^{, 12} ^{, 13} ^{, 14} ^{, 15} However, controlled studies have found no advantage of protein supplementation (up to about 100 grams per day or about 14 grams immediately following exercise) for improving strength or body composition as long as the diet already supplies typical amounts of protein and calories.¹⁶ ^{, 17} ^{, 18}
Get your carbs	Carbohydrates may be the most important nutrient for sports performance, as they are the most efficient fuel and can be stored in the muscle and liver as readily available energy.
Get your carbs Carbohydrates are the most efficient fuel for energy production and can also be stored as glycogen in muscle and liver, functioning as a readily available energy source for prolonged, strenuous exercise. For these reasons, carbohydrates may be the most important nutrient for sports performance.¹⁹ Depending on training intensity and duration, athletes require up to 4.5 grams of carbohydrates per day per pound of body weight or 60 to 70% of total dietary calories from carbohydrates, whichever is greater.²⁰ ^{, 21} Emphasizing grains, starchy vegetables, fruits, low-fat dairy products, and carbohydrate-replacement beverages, along with reducing intake of fatty foods, results in a relatively high-carbohydrate diet. Carbohydrate beverages should be consumed during endurance training or competition (30 to 70 grams of carbohydrate per hour) to help prevent carbohydrate depletion that might otherwise occur near the end of the exercise period. Standard sport drinks containing 6 to 8% carbohydrates can be used during exercise to support both carbohydrate and fluid needs, but these should not contain large amounts of fructose, which can cause gastrointestinal distress.²² At the end of endurance exercise, body carbohydrate stores must be replaced to prepare for the next session. This replacement can be achieved most rapidly if 40 to 60 grams of carbohydrate are consumed right after exercise, repeating this intake every hour for at least five hours after the event.²³ High-density carbohydrate beverages containing 20 to 25% carbohydrate are useful for immediate post-exercise repletion. Adding protein to carbohydrate intake immediately after exercise may be helpful for improving recovery of glycogen (carbohydrate) stores after exercise according to some,²⁴ ^{, 25} ^{, 26} though not all,²⁷ ^{, 28} ^{, 29} ^{, 30} ^{, 31} controlled studies. It appears that adding protein during the post-exercise period is not necessary when carbohydrate intake is high enough (about 0.55 grams per pound of body weight).³² Carbohydrate loading, or “super-compensation,” is a pre-event strategy that improves performance for some endurance athletes.³³ ^{, 34} Carbohydrate-loading can be achieved by consuming a 70% carbohydrate diet (or 4.5 grams per pound of body weight) for three to five days before competition, while gradually reducing training time, and ending with a day of no training while continuing the diet until the event date.
Hydrate, hydrate, hydrate	Loss of water and electrolytes due to sweating during exercise can result in decreased performance and other problems, so remember to drink plenty of water and electrolyte-balancing sports drinks prior to, during, and after exercise.
Hydrate, hydrate, hydrate Water is the most abundant substance in the human body and is essential for normal physiological function. Water loss due to sweating during exercise can result in decreased performance and other problems. The American College of Sports Medicine's recommenations for fluid consumption by exercisers were updated in 2007.³⁵ Fluids should be consumed prior to, during, and after exercise, especially when extreme conditions of climate, exercise intensity, and exercise duration exist. Enough fluids should be consumed up to two hours before exercise begins to produce urine that is not too dark or concentrated. The amount of fluid that should be consumed during exercise will vary depending on many factors, including personal sweating rate, climate, and type and duration of exercise. Exercisers should generally drink to satisfy their thirst, and should also monitor changes in their body weight during exercise. If weight loss approaches 2% of body weight, then fluid consumption has been inadequate to prevent dehydration. After exercise, enough additional fluid should be consumed to equal 150% of weight lost (24 ounces of fluid for each pound of weight loss). Some individuals may experience an increase in body weight during exercise; this can indicate that too much fluid has been consumed, which can lead to a potentially dangerous condition called hyponatremia (low blood sodium levels) even if electrolyte-containing sports drinks are used. A professional knowledgeable in sports medicine can help formulate an individualized plan for fluid consumption during exercise. Flavored sports drinks containing electrolytes are not necessary for fluid replacement during or after brief periods of exercise, but they may be more effective in encouraging the athlete to drink frequently and in larger amounts when needed.³⁶ Consuming fluids along with meals or salty snacks before and after exercise will also encourage sufficient fluid intake and may improve fluid retention in the body.³⁷
Make fat work for you	Some athletes have found success following a high-fat diet for a number of days and then briefly eating a high-carbohydrate diet prior to an endurance event.
Make fat work for you Some athletes have speculated that consuming a high-fat diet for two or more weeks prior to endurance competition might cause the body to shift its fuel utilization toward more abundant fat stores ("fat adaptation").³⁸ However, neither short-term nor long-term use of high-fat diets has been found to improve endurance performance compared with high-carbohydrate diets, and may even be detrimental due to depletion of glycogen stores.³⁹ ^{, 40} Following a high-fat diet with at least 24 hours of high carbohydrate intake has been suggested as a way to achieve fat adaptation while restoring glycogen levels before endurance competition.⁴¹ ^{, 42} While this concept is supported by physiological studies on athletes, no actual performance enhancement was shown when athletes were tested in competitive situations after a five- to six-day high-fat diet followed by 24 hours of high carbohydrate intake.⁴³ ^{, 44} ^{, 45} However, one controlled study found a small, significant benefit of ten days of high fat intake followed by three days of high carbohydrate intake.⁴⁶
Keep your eye on the GI	The glycemic index is a measure of a food’s ability to raise blood sugar levels. Before exercise, low-GI foods can be beneficial, while high-GI foods can quickly restore sugar stores after exercise.
Keep your eye on the GI The glycemic index (GI) is a measure of the ability of a food to raise blood sugar levels after it is eaten. Attention to the GI of carbohydrate sources may be helpful for increasing sports performance. Within one hour before exercise, consuming low GI carbohydrates (such as most fruits, pasta, legumes, or rice) provides carbohydrate without triggering a rapid rise in insulin that could result in hypoglycemia and prevent release of energy sources from fat cells.⁴⁷ Some controlled studies of cycling endurance have found that eating a pre-exercise meal of low-GI foods (lentils, rolled oats, or a combination of low GI foods) is more effective than consuming high-GI foods (potatoes, puffed rice, or a combination of high GI foods),⁴⁸ ^{, 49} ^{, 50} but most studies have found no significant advantage of low GI foods or fructose (a low-GI sugar) compared with other carbohydrate sources in a pre-exercise meal. ⁵¹ ^{, 52} ^{, 53} ^{, 54} ^{, 55} ^{, 56} ^{, 57} ^{, 58} After exercise, on the other hand, high-GI foods and beverages may be most helpful for quickly restoring depleted glycogen stores.⁵⁹

Supplements

What Are "Star" Ratings?

a7_3star Reliable and relatively consistent scientific data showing a substantial health benefit.

a7_2star Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

a7_1star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

Supplement	Amount	Why
Creatine Monohydrate (Non-Weight Bearing Endurance Exercise)	15 to 20 grams daily for five or six days	Taking this supplement for five or six days may improve performance of high-intensity, short-duration exercise (like sprinting) or sports with alternating low- and high-intensity efforts.
Creatine Monohydrate 15 to 20 grams daily for five or six days Creatine (creatine monohydrate) is used in muscle tissue for the production of phosphocreatine, a factor in the formation of ATP, the source of energy for muscle contraction and many other functions in the body.⁶⁰ ^{, 61} Creatine supplementation increases phosphocreatine levels in muscle, especially when accompanied by exercise or carbohydrate intake.⁶² ^{, 63} It may also increase exercise-related gains in lean body mass, though it is unclear how much of these gains represents added muscle tissue and how much is simply water retention.⁶⁴ Over 40 double-blind or controlled studies have found creatine supplementation (typically 136 mg per pound of body weight per day or 15 to 25 grams per day for five or six days) improves performance of either single or repetitive bouts of short-duration, high-intensity exercise lasting under 30 seconds each.⁶⁵ ^{, 66} ^{, 67} ^{, 68} ^{, 69} ^{, 70} ^{, 71} Examples of this type of exercise include weightlifting; sprinting by runners, cyclists, or swimmers; and many types of athletic training regimens for speed and power. About 15 studies did not report enhancement by creatine of this type of performance. These have been criticized for their small size and other research design problems, but it is possible that some people, especially elite athletes, are less likely to benefit greatly from creatine supplementation.⁷² Fewer studies have investigated whether creatine supplementation benefits continuous high- intensity exercise lasting 30 seconds or longer. Five controlled studies have found creatine beneficial for this type of exercise,⁷³ but one study found no benefit on performance of a military obstacle course run.⁷⁴ Most studies of endurance performance have found no advantage of creatine supplementation, except perhaps for non-weight bearing exercise such as cycling. ⁷⁵ ^{, 76} ^{, 77} Long-term use of creatine supplementation is typically done using smaller daily amounts (2 to 5 grams per day) after an initial loading period of several days with 20 grams per day. Very little research has been done to investigate the exercise performance effects of long-term creatine supplementation. One study reported that long-term creatine supplementation improved sprint performance.⁷⁸ Four controlled long-term trials using untrained women,⁷⁹ trained men,⁸⁰ or untrained older adults found that creatine improved gains made in strength and lean body mass from weight-training programs.⁸¹ ^{, 82} However, two controlled trials found no advantage of long-term creatine supplementation in weight-training football players.⁸³ ^{, 84} Creatine supplementation appears to increase body weight and lean body mass or fat-free mass, but these measurements do not distinguish between muscle growth and increased water content of muscle.⁸⁵ ^{, 86} A few double-blind studies using more specific muscle measurements have been done and found that combining creatine supplementation with strength training over several weeks does produce greater increases in muscle size compared with strength training alone.⁸⁷ ^{, 88} ^{, 89} What Else Is This Supplement Used For?

Supplement	Amount	Why
Multivitamin (Multi-Nutrient Deficiency)	If deficient: 100% Daily Value	When an athlete’s diet isn’t enough, taking a multivitamin–mineral can give the body the nutrition it needs for exercise.
Multivitamin If deficient: 100% Daily Value Many athletes do not eat an optimal diet, especially when they are trying to control their weight while training strenuously.⁹⁰ These athletes may experience micronutrient deficiencies that, even if marginal, could affect performance or cause health problems.⁹¹ ^{, 92} ^{, 93} ^{, 94} However, athletes who receive recommended daily allowances of vitamins and minerals from their diet do not appear to benefit from additional multivitamin-mineral supplements with increased performance.⁹⁵ ^{, 96} ^{, 97} Very little research has been done to evaluate the ergogenic effects of most vitamins or minerals other than those discussed in this article. Supplementation with selenium (180 mcg per day for 10 weeks) had no effect on the results of endurance training in one double-blind trial.⁹⁸ Vanadyl sulfate, a form of vanadium that may have an insulin-like action, was given to weight-training athletes in a double-blind trial, using 225 mcg per pound of body weight per day, but no effect on body composition was seen after 12 weeks, and effects on strength were inconsistent.⁹⁹ The importance of other individual vitamins and minerals is discussed elsewhere in this section.

Supplement	Amount	Why
Vitamin C (Reducing Pain and Speeding Muscle Strength Recovery after Intense Exercise)	400 mg daily for several days before and after intense exercise	Taking vitamin C for several days before and after intense exercise may reduce pain and speed muscle strength recovery.
Vitamin C 400 mg daily for several days before and after intense exercise Most research has demonstrated that strenuous exercise increases production of harmful substances called free radicals, which can damage muscle tissue and result in inflammation and muscle soreness. Exercising in cities or smoggy areas also increases exposure to free radicals. Antioxidants, including vitamin C and vitamin E, neutralize free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Regular exercise increases the efficiency of the antioxidant defense system, potentially reducing the amount of supplemental antioxidants that might otherwise be needed for protection. However, at least theoretically, supplements of antioxidant vitamins may be beneficial for older or untrained people or athletes who are undertaking an especially vigorous training protocol or athletic event.¹⁰⁰ ^{, 101} Placebo-controlled research, some of it double-blind, has shown that taking 400 to 3,000 mg of vitamin C per day for several days before and after intense exercise may reduce pain and speed up muscle strength recovery.¹⁰² ^{, 103} ^{, 104} However, taking vitamin C only after such exercise was not effective in another double-blind study.¹⁰⁵ While some research has reported that vitamin E supplementation in the amount of 800 to 1,200 IU per day reduces biochemical measures of free radical activity and muscle damage caused by strenuous exercise,¹⁰⁶ ^{, 107} ^{, 108} several studies have not found such benefits,¹⁰⁹ ^{, 110} ^{, 111} ^{, 112} and no research has investigated the effect of vitamin E on performance-related measures of strenuous exercise recovery. A combination of 90 mg per day of coenzyme Q10 and a very small amount of vitamin E did not produce any protective effects for marathon runners in one double-blind trial,¹¹³ while in another double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.¹¹⁴ In most well-controlled studies, exercise performance has not been shown to improve following supplementation with vitamin C, unless a deficiency exists, as might occur in athletes with unhealthy or irrational eating patterns.¹¹⁵ ^{, 116} Similarly, vitamin E has not benefited exercise performance, ¹¹⁷ ^{, 118} except possibly at high altitudes. ¹¹⁹ ^{, 120} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Asian Ginseng (Endurance Exercise, Muscle Strength)	2 grams of powdered root daily or 200 to 400 mg daily of an herbal extract standardized for 4% ginsenosides	Some early studies suggested there might be benefits of using Asian ginseng to improve athletic performance. One study reported increased pectoral and quadricep muscle strength in non-exercising men and women after supplementing with the herb.
Asian Ginseng 2 grams of powdered root daily or 200 to 400 mg daily of an herbal extract standardized for 4% ginsenosides Extensive but often poorly designed studies have been conducted on the use of Asian ginseng (Panax ginseng) to improve athletic performance.¹²¹ ^{, 122} While some early controlled studies suggested there might be benefits, several recent double-blind trials have found no significant effects of Asian ginseng on endurance exercise.¹²³ ^{, 124} ^{, 125} In many studies, it is possible that ginseng was used in insufficient amounts or for an inadequate length of time; a more effective regimen for enhancing endurance performance may be 2 grams of powdered root per day or 200 to 400 mg per day of an extract standardized for 4% ginsenosides, taken for eight to twelve weeks.¹²⁶ Short-term intense exercise has also not been helped by Asian ginseng according to double-blind trials,¹²⁷ ^{, 128} but one controlled study reported increased pectoral and quadricep muscle strength in non-exercising men and women after taking 1 gram per day of Asian ginseng for six weeks.¹²⁹ An extract of a related plant, American ginseng (Panax quinquefolius), was found ineffective at improving endurance exercise performance in untrained people after one week’s supplementation in a double-blind study.^[REF] What Else Is This Supplement Used For?

Supplement	Amount	Why
Casein Protein	Refer to label instructions	Casein protein is more slowly digested than other animal proteins, resulting in a slower, prolonged rise in blood levels of amino acids, so some speculate that it may better support protein synthesis by the body compared with proteins like whey protein that are more rapidly digested.
Casein Protein Casein protein is more slowly digested than other animal proteins, resulting in a slower yet more prolonged rise in blood levels of amino acids.¹³⁰ This has led to speculation that casein may support protein synthesis by the body for a longer period of time compared with proteins, such as whey protein, that are more rapidly digested. However, in two double blind trials, measurements of muscle protein synthesis after leg exercises were similar whether casein or whey protein (either 20 grams or 0.3 grams per 2.2 lbs body weight taken one hour after exercise) was consumed. Other double blind studies have shown that adding protein supplements to a weight-training program improves gains in muscle mass and strength, but only one trial has compared using casein alone to other proteins for improving body composition and muscle strength. In this controlled trial, overweight men were given a low-calorie diet along with a weight training exercise plan for three months. Men who followed this plan and also took 1.5 grams per day of predigested casein protein per 2.2 lbs body weight gained more strength and lean body mass, and lost more body fat than did men using a similar amount of whey protein along with the same diet and exercise plan. What Else Is This Supplement Used For?

Supplement	Amount	Why
Citrate (High-Intensity, Short- to Intermediate-Duration Exercise)	135 to 225 mg per pound of body weight dissolved in two cups of fluid and taken at least one hour before exercise	Taking sodium citrate may neutralize the acids produced during exercise that may interfere with energy production or muscle contraction. Some studies have found that sodium citrate typically improves short- to intermediate-duration exercise performance.
Coenzyme Q10	Refer to label instructions	Strenuous physical activity lowers blood levels of coenzyme Q10 (CoQ10). A few studies have reported that CoQ10 supplementation benefitted some trained athletes.
Coenzyme Q10 Strenuous physical activity lowers blood levels of coenzyme Q10 (CoQ10).¹³¹ However, while some studies have shown that CoQ10 improves the way the healthy body responds to exercise,¹³² other studies have found no improvement.¹³³ ^{, 134} ^{, 135} ^{, 136} A few studies, using at least four weeks of CoQ10 supplementation at 60 to 100 mg per day, have reported improvements in measures of work capacity ranging from 3 to 29% in sedentary people and from 4 to 32% in trained athletes.¹³⁷ However, recent double-blind and/or placebo-controlled trials in trained athletes, using performance measures such as time to exhaustion and total performance, have found either no significant improvement or significantly poorer results in those taking CoQ10.¹³⁸ ^{, 139} ^{, 140} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Creatine Monohydrate (High-Intensity, Short Duration Exercise or Sports with Alternating Low- and High-Intensity Efforts)	15 to 20 grams a day for five or six days	Supplementing with creatine may improve performance of non-weight bearing endurance exercises such as cycling.
Creatine Monohydrate 15 to 20 grams a day for five or six days Creatine (creatine monohydrate) is used in muscle tissue for the production of phosphocreatine, a factor in the formation of ATP, the source of energy for muscle contraction and many other functions in the body.¹⁴¹ ^{, 142} Creatine supplementation increases phosphocreatine levels in muscle, especially when accompanied by exercise or carbohydrate intake.¹⁴³ ^{, 144} It may also increase exercise-related gains in lean body mass, though it is unclear how much of these gains represents added muscle tissue and how much is simply water retention.¹⁴⁵ Over 40 double-blind or controlled studies have found creatine supplementation (typically 136 mg per pound of body weight per day or 15 to 25 grams per day for five or six days) improves performance of either single or repetitive bouts of short-duration, high-intensity exercise lasting under 30 seconds each.¹⁴⁶ ^{, 147} ^{, 148} ^{, 149} ^{, 150} ^{, 151} ^{, 152} Examples of this type of exercise include weightlifting; sprinting by runners, cyclists, or swimmers; and many types of athletic training regimens for speed and power. About 15 studies did not report enhancement by creatine of this type of performance. These have been criticized for their small size and other research design problems, but it is possible that some people, especially elite athletes, are less likely to benefit greatly from creatine supplementation.¹⁵³ Fewer studies have investigated whether creatine supplementation benefits continuous high- intensity exercise lasting 30 seconds or longer. Five controlled studies have found creatine beneficial for this type of exercise,¹⁵⁴ but one study found no benefit on performance of a military obstacle course run.¹⁵⁵ Most studies of endurance performance have found no advantage of creatine supplementation, except perhaps for non-weight bearing exercise such as cycling. ¹⁵⁶ ^{, 157} ^{, 158} Long-term use of creatine supplementation is typically done using smaller daily amounts (2 to 5 grams per day) after an initial loading period of several days with 20 grams per day. Very little research has been done to investigate the exercise performance effects of long-term creatine supplementation. One study reported that long-term creatine supplementation improved sprint performance.¹⁵⁹ Four controlled long-term trials using untrained women,¹⁶⁰ trained men,¹⁶¹ or untrained older adults found that creatine improved gains made in strength and lean body mass from weight-training programs.¹⁶² ^{, 163} However, two controlled trials found no advantage of long-term creatine supplementation in weight-training football players.¹⁶⁴ ^{, 165} Creatine supplementation appears to increase body weight and lean body mass or fat-free mass, but these measurements do not distinguish between muscle growth and increased water content of muscle.¹⁶⁶ ^{, 167} A few double-blind studies using more specific muscle measurements have been done and found that combining creatine supplementation with strength training over several weeks does produce greater increases in muscle size compared with strength training alone.¹⁶⁸ ^{, 169} ^{, 170} What Else Is This Supplement Used For?

Supplement	Amount	Why
DHEA (Improved Strength in Older Men)	100 mg daily	DHEA is a hormone that is used by the body to make the male sex hormone testosterone. In one double-blind trial, DHEA was effective for improving strength in older men.
DHEA 100 mg daily Dehydroepiandrosterone (DHEA) is a hormone produced by the adrenal glands that is used by the body to make the male sex hormone testosterone. In one double-blind trial, 100 mg per day of DHEA was effective for improving strength in older men,¹⁷¹ but 50 mg per day was ineffective in a similar study of elderly men and women.¹⁷² DHEA has not been effective for women or younger men in other studies.¹⁷³ ^{, 174} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Electrolytes (Ultra-Endurance Competition)	Refer to label instructions	Athletes participating in several hours of exercise, especially in hot, humid conditions, should use sodium-containing fluids to reduce the risk of performance-diminishing and possibly dangerous declines in blood sodium levels.
Electrolytes Electrolyte replacement is not as important as water intake in most athletic endeavors. It usually takes several hours of exercise in warm climates before sodium depletion becomes significant and even longer for depletions of potassium, chloride, and magnesium to occur.¹⁷⁵ Nonetheless, commercial sports drinks containing sodium and potassium may help to replace electrolytes lost in sweating during prolonged exercise, and will often make it easier to drink adequately as well as to retain more fluid.¹⁷⁶ Some athletes participating in several hours of exercise have developed a potentially dangerous condition called hyponatremia (low blood sodium levels) even when electrolyte-containing sports drinks were used.¹⁷⁷ This condition may be caused by fluid retention due to excessive drinking combined with natural reductions in kidney function during exercise, so some authorities caution against overdrinking during exercise, especially if the exerciser notices that his or her body weight goes up after prolonged physical activity.¹⁷⁸

Supplement	Amount	Why
Eleuthero	Refer to label instructions	Eleuthero supplementation may improve athletic performance, according to preliminary research. The herb strengthens the immune system and thus might reduce the risk of post-exercise infection.
Eleuthero Eleuthero (Eleutherococcus senticosus) supplementation may improve athletic performance, according to preliminary Russian research.¹⁷⁹ Other studies have been inconclusive and two recent double-blind studies showed no beneficial effect on endurance performance in trained men.¹⁸⁰ ^{, 181} ^{, 182} Eleuthero strengthens the immune system and thus might reduce the risk of post-exercise infection. Although some doctors suggest taking 1 to 4 ml (0.2 to 0.8 tsp) of fluid extract of eleuthero three times per day, evidence supporting the use of this herb to enhance athletic performance remains weak. What Else Is This Supplement Used For?

Supplement	Amount	Why
Glutamine (Post-Exercise Infection)	5 grams after exercise, then again two hours later	The amino acid glutamine may benefit athlete’s immune systems. Double-blind trials giving athletes glutamine reported 81% having no subsequent infection compared with 49% in the placebo group.
Glutamine 5 grams after exercise, then again two hours later The amino acid glutamine appears to play a role in several aspects of human physiology that might benefit athletes, including their muscle function and immune system.¹⁸³ Intense exercise lowers blood levels of glutamine, which can remain persistently low with overtraining.¹⁸⁴ Glutamine supplementation raises levels of growth hormone at an intake of 2 grams per day,¹⁸⁵ an effect of interest to some athletes because of the role of growth hormone in stimulating muscle growth,¹⁸⁶ and glutamine, given intravenously, was found to be more effective than other amino acids at helping replenish muscle glycogen after exercise.¹⁸⁷ However, glutamine supplementation (30 mg per 2.2 pounds body weight) has not improved performance of short-term, high-intensity exercise such as weightlifting or sprint cycling by trained athletes,¹⁸⁸ ^{, 189} and no studies on endurance performance or muscle growth have been conducted. Although the effects of glutamine supplementation on immune function after exercise have been inconsistent,¹⁹⁰ ^{, 191} double-blind trials giving athletes glutamine (5 grams after intense, prolonged exercise, then again two hours later) reported 81% having no subsequent infection compared with 49% in the placebo group.¹⁹² What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Iron (Iron-Deficiency Anemia)	Consult a qualified healthcare practitioner	Iron is a component of hemoglobin, which transports oxygen to muscle cells. In cases of iron deficiency, taking iron may restore levels and improve athletic performance.
Iron Consult a qualified healthcare practitioner Iron is important for an athlete because it is a component of hemoglobin, which transports oxygen to muscle cells. Some athletes, especially women, do not get enough iron in their diet. In addition, for reasons that are unclear, endurance athletes, such as marathon runners, frequently have low body-iron levels.¹⁹³ ^{, 194} ^{, 195} However, anemia in athletes is often not due to iron deficiency and may be a normal adaptation to the stress of exercise.¹⁹⁶ Supplementing with iron is usually unwise unless a deficiency has been diagnosed. People who experience undue fatigue (an early warning sign of iron deficiency) should have their iron status evaluated by a doctor. Athletes who are found to be iron deficient by a physician are typically given 100 mg per day until blood tests indicate they are no longer deficient. Supplementing iron-deficient athletes with 100 to 200 mg per day of iron increased aerobic exercise performance in some,¹⁹⁷ ^{, 198} ^{, 199} though not all,²⁰⁰ ^{, 201} double-blind studies. A recent double-blind trial found that iron-deficient women who took 20 mg per day of iron for six weeks were able to perform knee strength exercises for a longer time without muscle fatigue compared with those taking a placebo.²⁰² What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Nitric Oxide	4 gram three times per day	It has been speculated that AAKG may increase production of nitric oxide, a substance known to enhance blood flow. In one study, AAKG improved measures of strength and short-term power performance in weight lifters.
Nitric Oxide 4 gram three times per day AAKG (arginine alpha-ketoglutarate) is a compound made from the amino acid L-arginine and alpha-ketoglutarate (AKG) a substance formed in the body’s energy-generating process. It has been speculated that AAKG may increase production in muscles of nitric oxide, a substance known to have blood-flow-enhancing effects. A double-blind study gave trained weight lifters either 4 grams of AAKG or a placebo three times a day during an eight-week weight-training regimen. AAKG had no effect on body composition but did improve measures of strength and short-term power performance.²⁰³ What Else Is This Supplement Used For?

Supplement	Amount	Why
Phosphatidylserine (Athletic Performance and Enhanced Endurance)	750 mg daily	In a study of active young men, supplementation with phosphatidylserine increased the time the men could exercise until exhaustion by approximately 25%.
Phosphatidylserine 750 mg daily In a double-blind study of active young men, supplementation with 750 of soybean-derived phosphatidylserine per day for 10 days increased the time the men could exercise until exhaustion by approximately 25%.²⁰⁴ Longer studies are needed to determine whether this effect would persist with continued supplementation. What Else Is This Supplement Used For?

Supplement	Amount	Why
Pyruvate	100 grams of a combination of dihydroxyacetone and pyruvate	One group of researchers has reported that a combination of dihydroxyacetone and pyruvate enhanced the endurance of certain muscles.
Pyruvate 100 grams of a combination of dihydroxyacetone and pyruvate One group of researchers in two small, controlled trials has reported that 100 grams of a combination of dihydroxyacetone and pyruvate enhanced the endurance of certain muscles in untrained men.²⁰⁵ ^{, 206} Three controlled studies of untrained individuals using a combination of 6 to 10 grams per day of pyruvate and an exercise program reported greater effects on weight loss and body fat compared with those taking a placebo with the exercise program.²⁰⁷ ^{, 208} ^{, 209} However, in a study of healthy untrained women undergoing an exercise program, supplementing with 5 grams of pyruvate twice a day had no effect on exercise performance.²¹⁰ Studies of pyruvate supplementation on exercise performance in trained athletes have also failed to demonstrate any beneficial effect. Seven grams per day did not improve aerobic exercise performance in cyclists,²¹¹ and an average of 15 grams per day did not improve anaerobic performance or body composition in football players.²¹² More recently, evidence has appeared casting doubt on the ability of high levels (an average exceeding 15 grams per day depending upon body weight) of pyruvate to improve exercise capacity in a weight-lifting study.²¹³ What Else Is This Supplement Used For?

Supplement	Amount	Why
Pyruvate (Improving Body Composition with Strength Training in Untrained People)	Refer to label instructions	Three controlled studies of people using a combination of pyruvate and an exercise program reported positive effects on weight loss and body fat.
Pyruvate One group of researchers in two small, controlled trials has reported that 100 grams of a combination of dihydroxyacetone and pyruvate enhanced the endurance of certain muscles in untrained men.²¹⁴ ^{, 215} Three controlled studies of untrained individuals using a combination of 6 to 10 grams per day of pyruvate and an exercise program reported greater effects on weight loss and body fat compared with those taking a placebo with the exercise program.²¹⁶ ^{, 217} ^{, 218} However, in a study of healthy untrained women undergoing an exercise program, supplementing with 5 grams of pyruvate twice a day had no effect on exercise performance.²¹⁹ Studies of pyruvate supplementation on exercise performance in trained athletes have also failed to demonstrate any beneficial effect. Seven grams per day did not improve aerobic exercise performance in cyclists,²²⁰ and an average of 15 grams per day did not improve anaerobic performance or body composition in football players.²²¹ More recently, evidence has appeared casting doubt on the ability of high levels (an average exceeding 15 grams per day depending upon body weight) of pyruvate to improve exercise capacity in a weight-lifting study.²²² What Else Is This Supplement Used For?

Supplement	Amount	Why
Quercetin (Post-Exercise Infection)	500 mg twice a day	In one study, quercetin lowered the incidence of upper respiratory tract infections in athletes following intensive exercise.
Quercetin 500 mg twice a day In a double-blind study of trained athletes, the incidence of upper respiratory tract infections following a three-day period of intensive exercise was significantly lower in people who took quercetin than in those who received a placebo (5% versus 45%).²²³ The amount of quercetin used was 500 mg twice a day, beginning three weeks before, and continuing for two weeks after, the intensive exercise. What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Rhodiola (General Endurance)	200 mg of an herbal extract, standardized to contain 3% rosavin plus 1% salidroside, taken one hour before endurance exercise	In a double-blind trial, healthy volunteers who received an extract of the herb Rhodiola rosea one hour before an endurance-exercise test saw significantly increased endurance, as measured by the time it took to become exhausted.
Rhodiola 200 mg of an herbal extract, standardized to contain 3% rosavin plus 1% salidroside, taken one hour before endurance exercise In a double-blind trial, healthy volunteers received 200 mg of an extract of Rhodiola rosea (standardized to contain 3% rosavin plus 1% salidroside) or a placebo one hour prior to an endurance-exercise test. Compared with placebo, rhodiola significantly increased endurance, as measured by the time it took to become exhausted.²²⁴ However, after daily use of rhodiola for four weeks, the herb no longer enhanced short-term endurance. Consequently, if rhodiola is being considered as an exercise aid, it should be used only occasionally. What Else Is This Supplement Used For?

Supplement	Amount	Why
Soy (Exercise Recovery)	33 to 40 grams daily	In one study, elderly men participating in a strength training program who took a supplement containing protein (part of which was soy protein) immediately following exercise saw significant gains in muscle growth and lean body mass.
Soy 33 to 40 grams daily In one preliminary study, elderly men participating in a 12-week strength training program took a liquid supplement containing 10 grams of protein (part of which was soy protein), 7 grams of carbohydrate, and 3 grams of fat either immediately following exercise or two hours later.²²⁵ Men taking the supplement immediately following exercise experienced significantly greater gains in muscle growth and lean body mass than those supplementing two hours later, but strength gains were no different between the two groups. A controlled study of female gymnasts found that adding 0.45 grams of soy protein (0.45 grams per pound of body weight per day) to a diet that was adequate in protein during a four-month training program did not improve lean body mass compared with a placebo.²²⁶ No research has compared different sources of protein to see whether one source, such as soy protein, has a better or more consistent effect on exercise recovery or the results of strength training. What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Vitamin C (Vitamin C Deficiency)	If deficient: 100 to 200 mg daily	Antioxidants, including vitamin C, neutralize exercise-related free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Especially in cases of vitamin C deficiency, supplementing with the vitamin may improve exercise performance.
Vitamin C If deficient: 100 to 200 mg daily Most research has demonstrated that strenuous exercise increases production of harmful substances called free radicals, which can damage muscle tissue and result in inflammation and muscle soreness. Exercising in cities or smoggy areas also increases exposure to free radicals. Antioxidants, including vitamin C and vitamin E, neutralize free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Regular exercise increases the efficiency of the antioxidant defense system, potentially reducing the amount of supplemental antioxidants that might otherwise be needed for protection. However, at least theoretically, supplements of antioxidant vitamins may be beneficial for older or untrained people or athletes who are undertaking an especially vigorous training protocol or athletic event.²²⁷ ^{, 228} Placebo-controlled research, some of it double-blind, has shown that taking 400 to 3,000 mg of vitamin C per day for several days before and after intense exercise may reduce pain and speed up muscle strength recovery.²²⁹ ^{, 230} ^{, 231} However, taking vitamin C only after such exercise was not effective in another double-blind study.²³² While some research has reported that vitamin E supplementation in the amount of 800 to 1,200 IU per day reduces biochemical measures of free radical activity and muscle damage caused by strenuous exercise,²³³ ^{, 234} ^{, 235} several studies have not found such benefits,²³⁶ ^{, 237} ^{, 238} ^{, 239} and no research has investigated the effect of vitamin E on performance-related measures of strenuous exercise recovery. A combination of 90 mg per day of coenzyme Q10 and a very small amount of vitamin E did not produce any protective effects for marathon runners in one double-blind trial,²⁴⁰ while in another double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.²⁴¹ In most well-controlled studies, exercise performance has not been shown to improve following supplementation with vitamin C, unless a deficiency exists, as might occur in athletes with unhealthy or irrational eating patterns.²⁴² ^{, 243} Similarly, vitamin E has not benefited exercise performance, ²⁴⁴ ^{, 245} except possibly at high altitudes. ²⁴⁶ ^{, 247} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Vitamin E (Exercise Recovery, High-Altitude Exercise Performance)	400 IU daily	Antioxidants, including vitamin E, neutralize exercise-related free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Vitamin E has been shown to benefit exercise performance at high altitudes.
Vitamin E 400 IU daily Most research has demonstrated that strenuous exercise increases production of harmful substances called free radicals, which can damage muscle tissue and result in inflammation and muscle soreness. Exercising in cities or smoggy areas also increases exposure to free radicals. Antioxidants, including vitamin C and vitamin E, neutralize free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Regular exercise increases the efficiency of the antioxidant defense system, potentially reducing the amount of supplemental antioxidants that might otherwise be needed for protection. However, at least theoretically, supplements of antioxidant vitamins may be beneficial for older or untrained people or athletes who are undertaking an especially vigorous training protocol or athletic event.²⁴⁸ ^{, 249} Placebo-controlled research, some of it double-blind, has shown that taking 400 to 3,000 mg of vitamin C per day for several days before and after intense exercise may reduce pain and speed up muscle strength recovery.²⁵⁰ ^{, 251} ^{, 252} However, taking vitamin C only after such exercise was not effective in another double-blind study.²⁵³ While some research has reported that vitamin E supplementation in the amount of 800 to 1,200 IU per day reduces biochemical measures of free radical activity and muscle damage caused by strenuous exercise,²⁵⁴ ^{, 255} ^{, 256} several studies have not found such benefits,²⁵⁷ ^{, 258} ^{, 259} ^{, 260} and no research has investigated the effect of vitamin E on performance-related measures of strenuous exercise recovery. A combination of 90 mg per day of coenzyme Q10 and a very small amount of vitamin E did not produce any protective effects for marathon runners in one double-blind trial,²⁶¹ while in another double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.²⁶² In most well-controlled studies, exercise performance has not been shown to improve following supplementation with vitamin C, unless a deficiency exists, as might occur in athletes with unhealthy or irrational eating patterns.²⁶³ ^{, 264} Similarly, vitamin E has not benefited exercise performance, ²⁶⁵ ^{, 266} except possibly at high altitudes. ²⁶⁷ ^{, 268} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Whey Protein	20 grams daily up to 1.2 grams of per 2.2 of pounds body weight per day	Animal studies suggest that whey protein can increase gains in lean body mass resulting from exercise. One study found that people taking whey protein improved their performance on a test of short-term intense cycling exercise.
Whey Protein 20 grams daily up to 1.2 grams of per 2.2 of pounds body weight per day Animal studies suggest that whey protein can increase gains in lean body mass resulting from exercise.²⁶⁹ A controlled trial found that six weeks of strength training while taking 1.2 grams of whey protein per 2.2 of pounds body weight per day resulted in greater gains in lean body mass, but improved only one out of four strength tests.²⁷⁰ Another controlled study found that people taking 20 grams per day of whey protein for three months performed better on a test of short-term intense cycling exercise than people taking a similar amount of milk protein (casein).²⁷¹ However, a double-blind trial found that men taking 1.5 grams per 2.2 lbs of body weight per day of predigested whey protein for 12 weeks along with a strength training exercise program gained only half as much lean body mass and had significantly smaller increases in strength compared with men using a similar amount of predigested casein along with strength training.²⁷² A controlled study of HIV-infected women found that adding whey protein to strength training exercise was no more effective than exercise alone for increasing strength or improving body composition.²⁷³ What Else Is This Supplement Used For?

Supplement	Amount	Why
Alpha Ketoglutarate (AKG)	Refer to label instructions	AKG is used by cells during growth and is especially important in healing muscle tissue. It has been speculated that AKG supplements might help improve strength or muscle-mass gains by weight lifters.
Alpha Ketoglutarate (AKG) AKG (alpha-ketoglutarate) is used by cells during growth and in healing from injuries and other wounds,²⁷⁴ and is especially important in the healing of muscle tissue.²⁷⁵ A controlled study found that intravenous AKG prevented a decline in protein synthesis in the muscles of patients recovering from surgery.²⁷⁶ ^{, 277} For these reasons, it has been speculated that oral AKG supplements might help improve strength or muscle-mass gains by weight lifters, but no research has been done to test this theory. What Else Is This Supplement Used For?

Supplement	Amount	Why
Arginine (Body Composition and Strength)	Refer to label instructions	At very high intakes, the amino acid arginine has increased growth hormone levels, which stimulate muscle growth. Trials combining weight training with arginine and ornithine showed decreases in body fat and increases in total strength and lean body mass.
Arginine At very high intakes (approximately 250 mg per 2.2 pounds of body weight), the amino acid arginine has increased growth hormone levels,²⁷⁸ an effect that has interested body builders due to the role of growth hormone in stimulating muscle growth.²⁷⁹ However, at lower amounts recommended by some manufacturers (5 grams taken 30 minutes before exercise), arginine failed to increase growth hormone release and may even have impaired the release of growth hormone in younger adults.²⁸⁰ Large quantities (170 mg per 2.2 pounds of body weight per day) of a related amino acid, ornithine, have also raised growth hormone levels in some athletes.²⁸¹ High amounts of arginine or ornithine do not appear to raise levels of insulin,²⁸² ^{, 283} another anabolic (bodybuilding) hormone. More modest amounts of a combination of these amino acids have not had measurable effects on any anabolic hormone levels during exercise.²⁸⁴ ^{, 285} Nonetheless, double-blind trials conducted by one group of researchers, combining weight training with either arginine and ornithine (500 mg of each, twice per day, five times per week) or placebo, found the amino-acid combination produced decreases in body fat,²⁸⁶ resulted in higher total strength and lean body mass, and reduced evidence of tissue breakdown after only five weeks.²⁸⁷ What Else Is This Supplement Used For?

Supplement	Amount	Why
Aspartic Acid	Refer to label instructions	Aspartic acid is an amino acid that participates in many biochemical reactions relating to energy and protein. Research suggests that it may help reduce fatigue during exercise.
Aspartic Acid Aspartic acid is a non-essential amino acid that participates in many biochemical reactions relating to energy and protein. Preliminary, though conflicting, animal and human research suggested a role for aspartic acid (in the form of potassium and magnesium aspartate) in reducing fatigue during exercise.²⁸⁸ However, most studies have found aspartic acid useless in improving either athletic performance or the body’s response to exercise.²⁸⁹ ^{, 290} ^{, 291} ^{, 292} ^{, 293}

Supplement	Amount	Why
Beta-Sitosterol with Beta-Sitosterol Glucoside (Post-Exercise Infection)	Refer to label instructions	Beta-sitosterol, found in many plants, has been shown in one trial to improve immune function in marathon runners when combined with B-sitosterol glucoside. This implies that beta-sitosterol might reduce infections in athletes who engage in intensive exercise.
Beta-Sitosterol with Beta-Sitosterol Glucoside Beta-sitosterol , (BSS) a natural sterol found in many plants, has been shown in a double-blind trial to improve immune function in marathon runners when combined with a related substance called B-sitosterol glucoside (BSSG).²⁹⁴ This implies that beta-sitosterol might reduce infections in athletes who engage in intensive exercise, though studies are still needed to prove this. The usual amount of this combination used in research is 20 mg of BSS and 200 mcg of BSSG three times per day.

Supplement	Amount	Why
Branched-Chain Amino Acids (Post-Exercise Infection at Extreme Temperatures)	Refer to label instructions	Some research has shown that branched-chain amino acids may support immune fuction and improve infection at high altitudes and prolong endurance performance in the heat.
Branched-Chain Amino Acids Some research has shown that supplemental branched-chain amino acids (BCAA) (typically 10 to 20 grams per day) do not result in meaningful changes in body composition,²⁹⁵ nor do they improve exercise performance or enhance the effects of physical training.²⁹⁶ ^{, 297} ^{, 298} ^{, 299} ^{, 300} ^{, 301} However, BCAA supplementation may be useful in special situations, such as preventing muscle loss at high altitudes and prolonging endurance performance in the heat.³⁰² ^{, 303} One controlled study gave triathletes 6 grams per day of BCAA for one month before a competition, then 3 grams per day from the day of competition until a week following. Compared with a placebo, BCAA restored depleted glutamine stores and immune factors that occur in elite athletes, and led to a reported one-third fewer symptoms of infection during the period of supplementation.³⁰⁴ Studies by one group of researchers suggest that BCAA supplementation may also improve exercise-induced declines in some aspects of mental functioning.³⁰⁵ ^{, 306} ^{, 307} What Else Is This Supplement Used For?

Supplement	Amount	Why
Cayenne	Refer to label instructions	Capsaicin, a constituent of cayenne, has been shown to reduce pain caused by osteoarthritis and provide relief from chronic low back pain.
Cayenne Capsaicin ointment , applied four times per day over painful joints in the upper or lower limbs, reduces pain caused by osteoarthritis,³⁰⁸ and a plaster containing capsaicin applied to the low back for several hours per day provided relief from chronic low back pain in one study.³⁰⁹ Other uses of cayenne or capsaicin for sports and fitness have not been studied. What Else Is This Supplement Used For?

Supplement	Amount	Why
Chromium	Refer to label instructions	Chromium may play a role in altering body composition. Research has suggested that chromium picolinate might increase fat loss and lean muscle tissue gain when used with a weight-training program.
Chromium Chromium , primarily in a form called chromium picolinate, has been studied for its potential role in altering body composition. Preliminary research in animals and humans suggested that chromium picolinate might increase fat loss and lean muscle tissue gain when used with a weight-training program.³¹⁰ ^{, 311} ^{, 312} However, most studies have found little to no effect of chromium on body composition or strength.³¹³ ^{, 314} ^{, 315} ^{, 316} ^{, 317} One group of researchers has reported significant reductions in body fat in double-blind trials using 200 to 400 mcg per day of chromium for six to twelve weeks in middle-aged adults,³¹⁸ ^{, 319} but the methods used in these studies have been criticized.³²⁰ What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Conjugated Linoleic Acid	Refer to label instructions	Conjugated linoleic acid may play a role in reducing body fat. Research has reported that CLA supplementation produces minor gains in muscle size and strength in weight-training men.
Conjugated Linoleic Acid Conjugated linoleic acid (CLA) is a slightly altered form of the essential fatty acid linoleic acid. Animal research suggests an effect of CLA supplementation on reducing body fat.³²¹ ^{, 322} Controlled human research has reported that 5.6 to 7.2 grams per day of CLA produces only non-significant gains in muscle size and strength in experienced and inexperienced weight-training men.³²³ ^{, 324} ^{, 325} A double-blind study of a group of trained men and women reported reduced body fat in the upper arm after 12 weeks of supplementation with 1.8 grams per day of CLA.³²⁶ Further research using more accurate techniques for measuring body composition is needed to confirm these findings. What Else Is This Supplement Used For?

Supplement	Amount	Why
Copper	Refer to label instructions	In one trial a combination of zinc and copper significantly reduced evidence of post-exercise free radical activity.
Copper In one double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.³²⁷ Exercise increases zinc losses from the human body, and severe zinc deficiency can compromise muscle function.³²⁸ ^{, 329} Athletes who do not eat an optimal diet, especially those who are trying to control their weight or use fad diets while exercising strenuously, may become deficient in zinc to the extent that performance or health is compromised.³³⁰ ^{, 331} One double-blind trial in women found that 135 mg per day of zinc for two weeks improved one measure of muscle strength.³³² Whether these women were zinc deficient was not determined in this study. A double-blind study of male athletes with low blood levels of zinc found that 20 mg per day of zinc improved the flexibility of the red blood cells during exercise, which could benefit blood flow to the muscles.³³³ No other studies of the effects of zinc supplementation in exercising people have been done. A safe amount of zinc for long-term use is 20 to 40 mg per day along with 1 to 2 mg of copper. Higher amounts should be taken only under the supervision of a doctor. What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Eucalyptus Topical	Refer to label instructions	Eucalyptus-based rubs have been found to warm muscles in athletes. This suggests that eucalyptus may help relieve minor muscle soreness when applied topically.
Eucalyptus Topical Eucalyptus -based rubs have been found to warm muscles in athletes.³³⁴ This suggests that eucalyptus may help relieve minor muscle soreness when applied topically, though studies are needed to confirm this possibility. What Else Is This Supplement Used For?

Supplement	Amount	Why
Gamma Oryzanol	Refer to label instructions	Gamma oryzanol is a mixture of sterols and ferulic acid esters. One trial using ferulic acid in trained weight lifters found significantly more weight gain and increased strength compared with placebo.
Gamma Oryzanol Gamma oryzanol is a mixture of sterols and ferulic acid esters. Despite claims that gamma oryzanol or its components increase testosterone levels, stimulate the release of endorphins, and promote the growth of lean muscle tissue, research has provided little support for these claims and has also shown gamma-oryzanol to be poorly absorbed.³³⁵ A recent nine-week, double-blind trial of 500 mg per day of gamma-oryzanol in weight lifters found no benefit compared with placebo in strength performance gains or circulating anabolic hormones.³³⁶ However, a small, double-blind trial using 30 mg per day of ferulic acid for eight weeks in trained weight lifters did find significantly more weight gain (though lean body mass was not measured) and increased strength in one of three measures compared with placebo.³³⁷ What Else Is This Supplement Used For?

Supplement	Amount	Why
Guaraná	Refer to label instructions	Some athletes take guaraná, which contains caffeine, during their training, although there is no scientific research to support this use.
Guaraná Some athletes take guaraná during their training; however, there is no scientific research to support this use. Guaraná contains caffeine. Another caffeine-containing herb sometimes used during training is kola nut. What Else Is This Supplement Used For?

Supplement	Amount	Why
HMB (Improving Body Composition with Strength Training in Untrained People)	3 grams daily	HMB, a breakdown product of an essential branched-chain amino acid, has a role in protein synthesis and might, therefore, improve muscle growth and overall body composition. Research suggests it might be effective only when combined with an exercise program in people who are not already highly trained athletes.
HMB 3 grams daily HMB (beta hydroxy-beta-methylbutyrate) is a metabolite (breakdown product) of leucine, one of the essential branched-chain amino acids. Biochemical and animal research show that HMB has a role in protein synthesis and might, therefore, improve muscle growth and overall body composition when given as a supplement. However, double-blind human research suggests that HMB may only be effective when combined with an exercise program in people who are not already highly trained athletes. Double-blind trials found no effect of 3 to 6 grams per day of HMB on body weight, body fat, or overall body composition in weight-training football players or other trained athletes.³³⁸ ^{, 339} ^{, 340} ^{, 341} ^{, 342} However, one double-blind study found that 3 grams per day of HMB increased the amount of body fat lost by 70-year old adults who were participating in a strength-training program for the first time.³⁴³ A double-blind study of young men with no strength-training experience reported greater improvements in muscle mass (but not in percentage body fat) when HMB was used in the amount of 17 mg per pound of body weight per day.³⁴⁴ However, another group of men in the same study given twice as much HMB did not experience any changes in body composition. What Else Is This Supplement Used For?

Supplement	Amount	Why
Kola	Refer to label instructions	Kola nut is a caffeine-containing herb sometimes used during athletic training.
Kola Some athletes take guaraná during their training; however, there is no scientific research to support this use. Guaraná contains caffeine. Another caffeine-containing herb sometimes used during training is kola nut.

Supplement	Amount	Why
L-Carnitine	Refer to label instructions	L-carnitine has been popular as a potential aid in improving athletic performance because of its role in converting fat to energy. Some studies have found that it improves certain measures of muscle physiology.
L-Carnitine L-carnitine , which is normally manufactured by the human body, has been popular as a potential ergogenic aid (i.e., having the ability to increase work capacity), because of its role in the conversion of fat to energy.³⁴⁵ However, while some studies have found that L-carnitine improves certain measures of muscle physiology, research on the effects of 2 to 4 grams of L-carnitine per day on performance have produced inconsistent results.³⁴⁶ L-carnitine may be effective in certain intense exercise activities leading to exhaustion,³⁴⁷ but recent studies have reported that L-carnitine supplementation does not benefit non-exhaustive or even marathon-level endurance exercise,³⁴⁸ ^{, 349} anaerobic performance,³⁵⁰ or lean body mass in weight lifters.³⁵¹ What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Magnesium	Refer to label instructions	Magnesium deficiency can reduce exercise performance and contribute to muscle cramps. Studies suggest that taking magnesium might improve performance, although possibly only for those who are deficient or who are not highly trained athletes.
Magnesium Magnesium deficiency can reduce exercise performance and contribute to muscle cramps, but sub-optimal intake does not appear to be a problem among most groups of athletes.³⁵² ^{, 353} Controlled trials suggest that magnesium supplementation might improve some aspects of physiology important to sports performance in some athletes,³⁵⁴ ^{, 355} but controlled and double-blind trials focusing on performance benefits of 212 to 500 mg per day of magnesium have been inconsistent.³⁵⁶ ^{, 357} ^{, 358} ^{, 359} ^{, 360} ^{, 361} It is possible that magnesium supplementation benefits only those who are deficient or who are not highly trained athletes. ³⁶² ^{, 363} What Else Is This Supplement Used For? See Drug Interactions

Supplement	Amount	Why
Medium-Chain Triglycerides	Refer to label instructions	Medium-chain triglycerides contain a class of fatty acids that are more rapidly absorbed and burned as energy than other fats. For this reason, athletes have been interested in their use, especially during prolonged endurance exercise.
Medium-Chain Triglycerides Medium chain triglycerides (MCT) contain a class of fatty acids found only in very small amounts in the diet; they are more rapidly absorbed and burned as energy than are other fats.³⁶⁴ For this reason, athletes have been interested in their use, especially during prolonged endurance exercise. However, no effect on carbohydrate sparing or endurance exercise performance has been shown with moderate amounts of MCT (30 to 45 grams over two to three hours).³⁶⁵ ^{, 366} Controlled trials using very large amounts of MCT (approximately 85 grams over two hours) have resulted in both increased and decreased performance,³⁶⁷ ^{, 368} while a double-blind trial found that 60 grams per day of MCT for two weeks had no effect on endurance performance.³⁶⁹ A controlled study found increased performance when MCTs were added to a 10% carbohydrate solution,³⁷⁰ but another study found no advantage of adding MCT,³⁷¹ and a third trial actually reported decreased performance with this combination, probably due to gastrointestinal distress, in athletes using MCTs.³⁷² What Else Is This Supplement Used For?

Supplement	Amount	Why
Methoxyisoflavone	Refer to label instructions	The developers of methoxyisoflavone, a member of the flavonoid family, claim that it builds bone and muscle without the side effects seen with hormones. One trial found that athletes who took it reduced their body fat more significantly than those taking placebo.
Methoxyisoflavone Methoxyisoflavone is a member of the family flavonoids (isoflavones). In a U.S. Patent, the developers of this substance claim, based on preliminary animal research, that it possesses anabolic (muscle-building and bone-building) effects without the side effects seen with either androgenic (male) hormones or estrogenic (female) hormones.³⁷³ A preliminary controlled trial found that strength-training athletes who took 800 mg per day of methoxyisoflavone for eight weeks experienced a significantly greater reduction in percentage body fat than those who took a placebo.³⁷⁴ Double-blind research is needed to confirm these findings. The U.S. patent also claims methoxyisoflavone reduces appetite and lowers blood cholesterol levels. Whether this claim is true has not yet been demonstrated in published scientific research. What Else Is This Supplement Used For?

Supplement	Amount	Why
Octacosanol	Refer to label instructions	Preliminary studies have suggested that octacosanol improves endurance, reaction time, and other measures of exercise capacity.
Octacosanol Wheat germ oil, which contains a waxy substance known as octacosanol, has been investigated as an ergogenic agent. Preliminary studies have suggested that octacosanol improves endurance, reaction time, and other measures of exercise capacity.³⁷⁵ In another preliminary trial, supplementation with 1 mg per day of octacosanol for eight weeks improved grip strength and visual reaction time, but it had no effect on chest strength, auditory reaction time, or endurance.³⁷⁶ What Else Is This Supplement Used For?

Supplement	Amount	Why
Ornithine Alpha-Ketoglutarate	Refer to label instructions	Ornithine alpha-ketoglutarate (OKG) is believed to facilitate muscle growth by enhancing the body’s release of anabolic hormones, but this is based on effects seen in hospitalized and elderly people, not published research.
Ornithine Alpha-Ketoglutarate Ornithine alpha-ketoglutarate (OKG) is formed from the amino acids ornithine and glutamine and is believed to facilitate muscle growth by enhancing the body’s release of anabolic hormones. While this effect has been found in studies on hospitalized patients and elderly people,³⁷⁷ ^{, 378} no studies on muscle growth in athletes using OKG have been published. What Else Is This Supplement Used For?

Supplement	Amount	Why
Ribose	Refer to label instructions	Ribose is a type of sugar used by the body to make the energy-containing substance adenosine triphosphate (ATP), which gets depleted during intense exercise. Reports have suggested that taking ribose might increase power during short, intense bouts of exercise.
Ribose Ribose is a type of sugar used by the body to make the energy-containing substance adenosine triphosphate (ATP). Intense exercise depletes muscle cells of ATP as well as the ATP precursors made from ribose,³⁷⁹ ^{, 380} though these deficits are typically replaced within minutes.³⁸¹ Unpublished reports suggested that ribose supplementation might increase power during short, intense bouts of exercise.³⁸² ^{, 383} However, in a double-blind study, exercisers took four grams of ribose four times per day during a six-day strength-training regimen, and no effects on muscle power or ATP recovery in exercised muscles were found.³⁸⁴ In two other controlled studies, either 10 grams of ribose per day for five days or 8 grams every 12 hours for 36 hours resulted in only minor improvements in some measures of performance during repetitive sprint cycling.³⁸⁵ ^{, 386} What Else Is This Supplement Used For?

Supplement	Amount	Why
Rice Protein	Refer to label instructions	Some athletes believe rice protein may also improve blood flow to muscle to enhance growth and repair. However, no research has investigated the effects of rice protein on athletic performance.
Rice Protein Compared with other protein supplements, rice protein has more of the amino acid arginine, and since arginine is a vasodilator that can enhance blood flow to tissues, some athletes believe rice protein may also improve blood flow to muscle to enhance growth and repair. However, no research has investigated the effects of rice protein on athletic performance. What Else Is This Supplement Used For?

Supplement	Amount	Why
Vitamin B-Complex	Refer to label instructions	B-complex vitamins are needed to produce energy from carbohydrates. Exercisers may have slightly increased requirements for some of the B vitamins, including vitamins B2, B6, and B5, athletic performance can suffer if these slightly increased needs are not met.
Vitamin B-Complex The B-complex vitamins are important for athletes, because they are needed to produce energy from carbohydrates. Exercisers may have slightly increased requirements for some of the B vitamins, including vitamin B2, vitamin B6, and vitamin B5 (pantothenic acid);³⁸⁷ athletic performance can suffer if these slightly increased needs are not met.³⁸⁸ However, most athletes obtain enough B vitamins from their diet without supplementation,³⁸⁹ and supplementation studies have found no positive effect on performance measures for vitamin B2,³⁹⁰ ^{, 391} vitamin B3 (niacin),³⁹² or vitamin B6.³⁹³ On the contrary, large amounts of niacin have been shown to impair endurance performance.³⁹⁴ What Else Is This Supplement Used For?

Supplement	Amount	Why
Yohimbe	Refer to label instructions	Yohimbine has shown an ability to stimulate the nervous system, promote the release of fat from fat cells, and affect the cardiovascular system.
Yohimbe The ability of yohimbine, a chemical found in yohimbe bark, to stimulate the nervous system,³⁹⁵ ^{, 396} promote the release of fat from fat cells,³⁹⁷ ^{, 398} and affect the cardiovascular system ³⁹⁹ has led to claims that yohimbe might help athletic performance or improve body composition. However, a double-blind study of men who were not dieting reported no effect of up to 43 mg per day of yohimbine on weight or body composition after six months.⁴⁰⁰ No research has tested yohimbe herb for effects on body composition, and no human research has investigated the ability of yohimbine or yohimbe to affect athletic performance. Other studies have determined that a safe daily amount of yohimbine is 15 to 30 mg.⁴⁰¹ However, people with kidney disorders should not take yohimbe, and side effects of nausea, dizziness, or nervousness may occur that necessitate reducing or stopping yohimbe supplementation. What Else Is This Supplement Used For?

Supplement	Amount	Why
Zinc	Refer to label instructions	Exercise depletes zinc, and severe zinc deficiency can compromise muscle function. One trial found that zinc improved muscle strength, and another study of athletes with low zinc levels found that zinc improved red blood cell flexibility during exercise, which could benefit blood flow to the muscles.
Zinc Exercise increases zinc losses from the human body, and severe zinc deficiency can compromise muscle function.⁴⁰² ^{, 403} Athletes who do not eat an optimal diet, especially those who are trying to control their weight or use fad diets while exercising strenuously, may become deficient in zinc to the extent that performance or health is compromised.⁴⁰⁴ ^{, 405} One double-blind trial in women found that 135 mg per day of zinc for two weeks improved one measure of muscle strength.⁴⁰⁶ Whether these women were zinc deficient was not determined in this study. A double-blind study of male athletes with low blood levels of zinc found that 20 mg per day of zinc improved the flexibility of the red blood cells during exercise, which could benefit blood flow to the muscles.⁴⁰⁷ No other studies of the effects of zinc supplementation in exercising people have been done. A safe amount of zinc for long-term use is 20 to 40 mg per day along with 1 to 2 mg of copper. Higher amounts should be taken only under the supervision of a doctor. What Else Is This Supplement Used For? See Drug Interactions

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Last Review: 08-17-2011

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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2013.

Topic Contents

Athletic Performance

Need to Know

Related Topics

About

About This Condition

Eating Right

The right diet is the key to managing many diseases and to improving general quality of life. For this condition, scientific research has found benefit in the following healthy eating tips.

Fuel up

Get enough protein

Get your carbs

Hydrate, hydrate, hydrate

Make fat work for you

Keep your eye on the GI

Supplements

What Are "Star" Ratings?

Creatine Monohydrate

Multivitamin

Vitamin C

Asian Ginseng

Casein Protein

Coenzyme Q10

Creatine Monohydrate

DHEA

Electrolytes

Eleuthero

Glutamine

Iron

Nitric Oxide

Phosphatidylserine

Pyruvate

Pyruvate

Quercetin

Rhodiola

Soy

Vitamin C

Vitamin E

Whey Protein

Alpha Ketoglutarate (AKG)

Arginine

Aspartic Acid

Beta-Sitosterol with Beta-Sitosterol Glucoside

Branched-Chain Amino Acids

Cayenne

Chromium

Conjugated Linoleic Acid

Copper

Eucalyptus Topical

Gamma Oryzanol

Guaraná

HMB

Kola

L-Carnitine

Magnesium

Medium-Chain Triglycerides

Methoxyisoflavone

Octacosanol

Ornithine Alpha-Ketoglutarate

Ribose

Rice Protein

Vitamin B-Complex

Yohimbe

Zinc

References