Parts Used & Where Grown
The neem tree, a member of the Meliaceae family, appears to have originated in India and Southeast Asia and been spread throughout drier lowland tropical and subtropical regions of Africa, the Middle East, the Americas, Australia, and South Pacific islands. The leaves, used as medicine, are generally available year-round as the tree is evergreen except during severe droughts or if exposed to frost.
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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.
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:
Apply a gel containing 2.5 to 5.0% extract twice per day
Neem gel has been shown to be effective at reducing plaque and bacterial levels in the mouth.
In a double-blind trial, 1 gram of leaf extract in gel twice per day was more effective than chlorhexidine or placebo gel at reducing plaque and bacteria levels in the mouth in 36 Indian adults. A similar trial found neem gel superior to placebo and equally effective as chlorhexidine at reducing plaque and bacteria levels in the mouth.
30 to 60 mg of freeze-dried bark extract twice per day
Neem bark extract led to a significant reduction in stomach acid levels and near complete healing of all people with duodenal ulcers in one trial.
Administration of 30 to 60 mg of freeze-dried bark extract twice per day led to a significant reduction in stomach acid levels and near complete healing of all people with duodenal ulcers over ten weeks time in a preliminary clinical trial.
Chamomile has a soothing effect on inflamed and irritated mucous membranes. It is also high in the flavonoid apigenin—another flavonoid that has inhibited growth of H. pylori in test tubes. Many doctors recommend drinking two to three cups of strong chamomile tea each day. The tea can be made by combining 3 to 5 ml of chamomile tincture with hot water or by steeping 2 to 3 tsp of chamomile flowers in the water, covered, for 10 to 15 minutes. Chamomile is also available in capsules; two may be taken three times per day.
1 gram of leaf extract in gel applied to teeth twice per day
Neem leaf extract has been shown to reduce plaque and bacteria levels in the mouth.
In a double-blind trial, 1 gram of leaf extract in gel twice per day was more effective than chlorhexidine or placebo gel at reducing plaque and bacteria levels in the mouth in 36 Indian adults. A similar trial found neem gel superior to placebo and equally effective as chlorhexidine at reducing plaque and bacteria levels in the mouth. These promising early studies should be followed by studies regarding prevention of cavities and relief from gingivitis or periodontal disease.
Use a cream containing seed extract, saponins of Sapindus mukerossi (reetha), and quinine hydrochloride (5 ml applied vaginally once at bedtime)
In one trial, a cream containing neem seed extract, saponins of reetha, and quinine hydrochloride eliminated all symptoms in 10 of 14 women with chlamydia.
In a double-blind, placebo-controlled trial, a cream containing seed extract, saponins of Sapindus mukerossi (reetha), and quinine hydrochloride (5 ml applied vaginally once at bedtime) eliminated all symptoms in 10 of 14 women with chlamydia compared with none of four women given placebo cream. Neither cream was effective in women with trichomoniasis or candidal vaginitis.
Traditional Use (May Not Be Supported by Scientific Studies)
Neem has a long history of use in the traditional medical systems of India (Ayurvedic, Unani-Tibb).1 Neem leaf and bark extracts are most consistently recommended in ancient medical texts and by herbal practitioners for gastrointestinal upsets, diarrhea and intestinal infections, skin ulcers and infections, and malaria.2 Neem twigs are the most regularly used toothbrush for a large portion of the population of India and other countries where the tree is common.3 The effectiveness of many of these uses has been confirmed in modern research studies, showing, for example, that neem bark extracts are effective for people with stomach ulcers, that leaf gel can effectively fight periodontal disease, and that leaf extracts can combat scabies infections.4, 5, 6 The claimed contraceptive effects of neem have been confirmed in some animal studies showing that seed extracts of neem are spermicidal.7
How It Works
How It Works
The major active constituents in neem are terpenoids such as azadirachtin, which are considered to be antimicrobial and insect repellant among many other actions, and fatty acids and possibly other compounds in neem oil.8, 9
How to Use It
Traditionally, neem has been administered as roughly 10 to 20 ml (2 to 4 teaspoons) of leaf juice or 2 to 4 grams (1/7 to 1/10 of an ounce) of powdered leaf two or three times per day.10 Leaf extract gel or toothpaste, 1 gram (1/5 of a teaspoon) in the morning and at bedtime brushed all over the mouth, has been used effectively for dental plaque.11 Freeze-dried neem bark extract (30 to 60 mg twice a day) has been shown helpful for people with stomach ulcers.12 Creams containing 5% or more of neem oil or neem extracts are typically applied at least twice per day for skin or vaginal infections. Neem oil (in a concentration of 1 to 4%) mixed in coconut, mustard, or other oil bases is used for repelling insects.13
Interactions with Supplements, Foods, & Other Compounds
Water extracts of neem leaf have been shown to decrease blood levels of chloroquine in rabbits, so these should not be combined until their safety can be demonstrated in humans.14
Interactions with Medicines
Neem leaf extracts and teas appear to be very safe at recommended intake levels with no significant reports of problems. Neem seed oil is more problematic and should be kept out of reach of children because of a report of Reye's syndrome–like symptoms in a few infants who consumed 5 ml of the oil and ultimately died.15 No deaths have been reported in adults, but because of the potential for severe adverse effects, the amount of neem used should not exceed the amount that has been safely used in research studies. Adults may sometimes have diarrhea, nausea, or stomach upset when taking neem oil.16 Neem should be avoided in pregnancy until its safety is demonstrated.
1. Schmutterer H, Ascher KRS, Isman MB, et al, eds. The Neem Tree:Azadirachta indicaA Juss and Other Meliaceous Plants. Weinheim, Germany: VCH, 1995.
2. Schmutterer H, Ascher KRS, Isman MB, et al, eds. The Neem Tree:Azadirachta indicaA Juss and Other Meliaceous Plants. Weinheim, Germany: VCH, 1995.
3. Ad Hoc Panel of the Board on Science and Technology for International Development, National Research Council. Neem: A Tree for Solving Global Problems. Washington, DC: National Academy Press, 1992.
4. Bandyopadhyay U, Biswas K, Sengupta A, et al. Clinical studies on the effect of Neem (Azadirachta indica) bark extract on gastric secretion and gastroduodenal ulcer. Life Sci2004;75:2867-78.
5. Pai MR, Acharya LD, Udupa N. The effect of two different dental gels and a mouthwash on plaque and gingival scores: a six-week clinical study. Int Dent J 2004;54:219-23.
6. Charles V, Charles SX. The use and efficacy of Azadirachta indica ADR ('Neem') and Curcuma longa ('Turmeric') in scabies. A pilot study. Trop Geogr Med 1992;44:178-81.
7. Garg S, Taluja V, Upadhyay SN, Talwar GP. Studies on the contraceptive efficacy of Praneem polyherbal cream. Contraception1993;48:591-6.
8. Rembold H. The azadirachtins—their potential for insect control. Econ Med Plant Res 1989;3:57-72.
9. Schmutterer H, Ascher KRS, Isman MB, et al, eds. The Neem Tree:Azadirachta indicaA Juss and Other Meliaceous Plants. Weinheim, Germany: VCH, 1995.
10. Khare CP. Indian Herbal Remedies. Berlin: Springer, 2004.
11. Pai MR, Acharya LD, Udupa N. Evaluation of antiplaque activity of Azadirachta indica leaf extract gel—a 6-week clinical study. J Ethnopharmacol2004;90:99-103.
12. Bandyopadhyay U, Biswas K, Sengupta A, et al. Clinical studies on the effect of Neem (Azadirachta indica) bark extract on gastric secretion and gastroduodenal ulcer. Life Sci2004;75:2867-78.
13. Mishra AK, Singh N, Sharma VP. Use of neem oil as a mosquito repellent in tribal villages of Mandla district, Madhya Pradesh. Indian J Malariol 1995;32:99-103.
14. Nwafor SV, Akah PA, Okoli CO, et al. Interaction between chloroquine sulphate and aqueous extract of Azadirachta indica A. Juss (Meliaceae) in rabbits. Acta Pharm 2003;53:305-11.
15. Sinniah D, Baskara G, Looi LM, Leong KL. Reye-like syndrome due to margosa oil poisoning: Report of a case with postmortem findings. Am J Gastroenterol 1982;77:158-61.
16. Caius JF, Mhaskar KS. The correlation between the chemical composition of anthelminthics and their therapeutic values in connection with the hookworm inquiry in the Madras Presidency. Indian J Med Res 1923;11:353-70.
Last Review: 06-08-2015
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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.