About Neem
Neem (Azadirachta indica) leaf and bark contain nimbidin, azadirachtin, gedunin, and quercetin. Best-supported indications are TOPICAL: dental plaque reduction (neem mouthwash RCTs show comparable plaque/gingivitis reduction to chlorhexidine in 4–6 week trials) and topical antifungal/insecticidal use. Oral supplementation for systemic effects (anti-parasitic, antidiabetic, anti-inflammatory) has limited and mostly poor-quality clinical evidence — small open-label studies dominate. SAFETY — significant: pediatric neem oil ingestion has caused fatal Reye-syndrome-like encephalopathy (multiple case series, India). Hepatotoxicity at high oral doses. Documented antifertility/contraceptive effect in animal studies; classically used as a folk contraceptive in India — avoid when trying to conceive. Pregnancy contraindicated. Avoid entirely in children. Hypoglycemic effect may potentiate diabetes medications.
What Neem supports
- Topical neem mouthwash reduces plaque/gingivitis comparably to chlorhexidine (small RCTs)
- Pediatric oral neem oil has caused fatal encephalopathy — never give to children
- Documented antifertility activity — avoid when trying to conceive or during pregnancy
How much Neem to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
200–1000
mg
Traditional Ayurvedic dosing for leaf powder is 1–3 g/day; extract doses cluster at 200–500 mg. No modern dose-finding RCT validates a therapeutic range for any indication.
Clinical evidence
Limited clinical evidence. Topical/oral-hygiene use is best-supported; systemic supplementation evidence is weak and overshadowed by documented pediatric toxicity.
Reference