The amino acid arginine has several roles in the body, such as assisting in wound healing, helping remove excess ammonia from the body, stimulating immune function, and promoting secretion of several hormones, including glucagon, insulin, and growth hormone.
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3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
2 to 3 grams three times per day
In one study, taking arginine improved the ability of angina sufferers to exercise. Detailed studies have proven that arginine works by stimulating blood vessel dilation.
Nitroglycerin and similar drugs cause dilation of arteries by interacting with nitric oxide, a potent stimulus for dilation. Nitric oxide is made from , a common amino acid. Blood cells in people with angina are known to make insufficient nitric oxide, which may in part be due to abnormalities of arginine metabolism. Taking 2 grams of arginine three times per day for as little as three days has improved the ability of angina sufferers to exercise. Seven of ten people with severe angina improved dramatically after taking 9 grams of arginine per day for three months in an uncontrolled study. Detailed studies have investigated the mechanism of arginine and have proven it operates by stimulating blood vessel dilation.
Congestive Heart Failure
5.6 to 15 grams per day with a doctor's supervision
The body needs arginine to make nitric oxide, which increases blood flow. This process is impaired in people with CHF. It also has been shown to improve kidney function in people with CHF.
The body needs , another amino acid, to make nitric oxide, which increases blood flow. This process is impaired in people with CHF. Arginine supplementation (5.6–12.6 grams per day) has been used successfully in double-blind trials to treat CHF.A double-blind trial has also found that arginine supplementation (5 grams three times daily) improves kidney function in people with CHF.
1,670 to 2,800 mg daily
Blood vessels need arginine to dilate and form an erection. Supplementing with arginine has been shown to help men with erectile dysfunction in some studies.
Dilation of blood vessels necessary for a normal erection depends on a substance called nitric oxide, and nitric oxide formation depends on the amino acid . In a preliminary trial, men with ED were given 2,800 mg of arginine per day for two weeks. Six of the 15 men in the trial were helped, though none improved while taking placebo. In a larger double-blind trial, men with ED were given 1,670 mg of arginine per day or a matching placebo for six weeks. Arginine supplementation was found to be particularly effective at improving ED in men with abnormal nitric oxide metabolism. Although little is known about how effective arginine will be for men with ED or which subset of these men would be helped, available research looks promising and suggests that at least some men are likely to benefit.
HIV and AIDS Support and Preservation of Lean Body Mass (Glutamine, HMB)
1.5 grams of HMB, 7 grams of L-glutamine, and 7 grams of L-arginine twice per day
The combination of glutamine, arginine, and HMB may prevent loss of lean body mass in people with AIDS-associated wasting.
The combination of glutamine, , and the amino acid derivative, hydroxymethylbutyrate (HMB), may prevent loss of lean body mass in people with AIDS-associated wasting. In a double-blind trial, AIDS patients who had lost 5% of their body weight in the previous three months received either placebo or a nutrient mixture containing 1.5 grams of HMB, 7 grams of L-glutamine, and 7 grams of L-arginine twice daily for eight weeks. Those supplemented with placebo gained an average of 0.37 pounds, mostly fat, but lost lean body mass. Those taking the nutrient mixture gained an average of 3 pounds, 85% of which was lean body weight.
Refer to label instructions
Arginine supports relaxation of the blood vessels and may help reduce blood pressure.
The amino acid is needed by the body to make nitric oxide, a substance that allows blood vessels to dilate, thus leading to reduced blood pressure. Other mechanisms by which arginine may lower blood pressure include increasing antioxidant capacity and modulating the renin-angiotensin-aldosterone system that regulates salt and water balance. Clinical evidence from small trials shows oral arginine supplementation can modestly reduce systolic and diastolic blood pressures. Intravenous arginine, at 500 mg per kilogram of body weight, has been found in two trials to reduce blood pressure in hypertensive subjects, and the effect may be greater in those whose hypertension is salt-sensitive. Meta-analyses have shown arginine supplementation at doses of 8–11 grams per day can lower systolic blood pressure by 2.2–5.4 mmHg and diastolic blood pressure by 2.7–3.1 mmHg. In a placebo-controlled trial that enrolled 25 middle-aged adults with mildly elevated blood pressure, an arginine-based supplement providing 2.4 grams of arginine daily improved blood vessel function, but its blood pressure lowering effect was not statistically significant.
4 grams daily
The amino acid arginine is needed to produce sperm. Research shows that several months of L-arginine supplementation increases sperm count, quality, and fertility.
, an amino acid found in many foods, is needed to produce sperm. Research, most of which is preliminary shows that several months of L-arginine supplementation increases sperm count, quality, and fertility. However, when the initial sperm count was extremely low (such as less than 10 million per ml), L-arginine supplementation produced little or no benefit. While some pregnancies have been attributed to arginine supplementation in preliminary reports, no controlled research has confirmed these claims. For infertile men with sperm counts greater than 10 million per milliliter, many doctors recommend up to 4 grams of L-arginine per day for several months.
Pre- and Post-Surgery Health
12.5 to 18.75 grams daily before and after surgery
The amino acid arginine has a role in immune function, infection prevention, and tissue repair after injury, including surgery.
The amino acid has a role in immune function, infection prevention, and tissue repair after injury, including surgery. Animal research suggests that supplemental arginine may improve the outcomes in cardiovascular and colon surgeries. Other animal studies suggest a possible role for arginine in prevention of adhesions, a painful type of internal scarring that can occur with surgery. Human trials of formulas including arginine are discussed below, but the benefits of supplemental arginine alone have not been studied in surgery patients.
Refer to label instructions
In one study in which pregnant women at an increased risk of developing preeclampsia received either arginine or a placebo, the arginine group had a significantly lower incidence of preeclampsia compared with the placebo group.
In a double-blind study, 100 pregnant women at increased risk of developing preeclampsia received 3 grams of arginine once a day or a placebo, starting in the 20th week of gestation and continuing until delivery. The incidence of preeclampsia was significantly lower by 74% in the arginine group than in the placebo group (6.1% vs. 23.4%).
Sickle Cell Anemia and Pulmonary Hypertension
100 mg per 2.2 lbs (1 kg) of body weight, three times per day
People with pulmonary hypertension (a life-threatening complication of sickle cell anemia) who received L-arginine had significant improvement in one study.
In a preliminary study, individuals with pulmonary hypertension (a life-threatening complication of sickle cell anemia) received in the amount of 100 mg per 2.2 pounds of body weight, three times per day for five days. L-arginine treatment resulted in a significant improvement in pulmonary hypertension, as determined by a 15% decline in the pulmonary artery systolic pressure. Longer-term studies are needed to confirm these preliminary results.
Athletic Performance and Body Composition and Strength
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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.
At very high intakes (approximately 250 mg per 2.2 pounds of body weight), the has increased growth hormone levels, an effect that has interested body builders due to the role of growth hormone in stimulating muscle growth. 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. 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. High amounts of arginine or ornithine do not appear to raise levels of insulin, 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.
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, resulted in higher total strength and lean body mass, and reduced evidence of tissue breakdown after only five weeks.
Female Infertility and In Vitro Fertilization
Refer to label instructions
Supplementing with L-arginine has been shown to improve fertility in women with a history of failed attempts at in vitro fertilization.
Supplementation with the amino acid, (16 grams per day), has been shown to improve fertilization rates in women with a previous history of failed attempts at in vitro (test tube) fertilization.
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The amino acid arginine may both protect the stomach and increase its blood flow.
Various amino acids have shown promise for people with gastritis. In a double-blind trial, taking 200 mg of cysteine four times daily provided significant benefit for people with bleeding gastritis caused by NSAIDs (such as aspirin). Cysteine is a sulfur-containing amino acid that stimulates healing of gastritis. In a preliminary trial, 1–4 grams per day of NAC (N-acetyl cysteine) given to people with atrophic gastritis for four weeks appeared to increase healing.Glutamine, another amino acid is a main energy source for cells in the stomach and supplementation may increase blood flow to this region. Patients in surgical intensive care units often develop gastrointestinal problems related to a glutamine deficiency. When burn victims were supplemented with glutamine, they did not develop stress ulcers, even after several operations. Nevertheless, it remains unclear to what extent glutamine supplementation might prevent or help existing gastritis. Preliminary evidence suggests the amino acid may both protect the stomach and increase its blood flow, but research has yet to investigate the effects of arginine supplementation in people with gastritis.
Refer to label instructions
Arginine appears to improve wound healing by increasing protein synthesis.
supplementation increases protein synthesis and improves wound healing in animals. Two controlled trials have shown increased tissue synthesis in surgical wounds in people given 17–25 grams of oral arginine per day.
How It Works
How to Use It
Most people do not need to take extra arginine. While some people with serious infections, burns, or other trauma should take arginine, appropriate amounts must be determined by a doctor. Levels used in research vary considerably (2–30 grams per day). Most research on cardiovascular disease has used between 6 and 20 grams per day. Optimal intakes remain unknown and are likely to vary depending upon the individual.
Where to Find It
Dairy, meat and poultry, and fish are good sources of arginine. Nuts and chocolate also contain significant amounts of this amino acid.
Interactions with Supplements, Foods, & Other Compounds
Arginine works with ornithine in the synthesis of growth hormone.
Interactions with Medicines
For most people, arginine has so far appeared to be free of obvious side effects. However, longer-term studies are needed to confirm its safety.
In a double-blind study, supplementation with 9 grams of arginine per day for six months, beginning within 3 to 21 days after a heart attack, resulted in an increase in the mortality rate.1 Therefore, people who have recently suffered a heart attack should probably not take large amounts of arginine. Arginine is beneficial for other manifestations of heart disease, such as heart failure and angina. However, because of the potential for arginine to cause adverse effects in heart patients, people with heart disease should consult a doctor before taking arginine.
There have been two case reports of severe allergic reactions following intravenous administration of L-arginine;2 however, allergic reactions have not been reported after oral administration.
People with kidney or liver disease should consult their doctor before supplementing with arginine. Some doctors believe that people with herpes (either cold sores or genital herpes) should not take arginine supplements, because of the possibility that arginine might stimulate replication of the virus.
Administration of large amounts of arginine to animals has been found both to promote3 and to interfere with cancer growth.4 In preliminary research, high intake (30 grams per day) of arginine has increased cancer cell growth in humans.5 On the other hand, in people with cancer, arginine has been found to stimulate the immune system.6 At this time it remains unclear whether arginine is dangerous or helpful for people with cancer.
1. Schulman SP, Becker LC, Kass DA, et al. L-arginine therapy in acute myocardial infarction: the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) randomized clinical trial. JAMA 2006;295:58-64.
2. Resnick DJ, Softness B, Murphy AR, et al. Case report of an anaphylactoid reaction to arginine. Ann Allergy Asthma Immunol 2002;88:67-8.
3. Park KGM. The immunological and metabolic effects of L-arginine in human cancer. Proc Nutr Soc 1993;52:387-401.
4. Takeda Y, Tominga T, Tei N, et al. Inhibitory effect of L-arginine on growth of rat mammary tumors induced by 7,12-dimethlybenz(a)anthracine. Cancer Res 1975;35:2390-3.
5. Park KGM. The immunological and metabolic effects of L-arginine in human cancer. Proc Nutr Soc 1993;52:387-401.
6. Brittenden J, Park KGM, Heys SD, et al. L-arginine stimulates host defenses in patients with breast cancer. Surgery 1994;115:205-12.
Last Review: 06-01-2015
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The information presented by TraceGains 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. 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 December 2023.