What clinical trials have tested moringa leaf extracts at doses under 500 mg in humans and what adverse events did they report?

1. Trials found — mostly gram doses, not sub-500 mg

A systematic look across recent reviews and trial summaries shows human interventional work using dry leaf powder or extracts in the gram range: a randomized trial in prediabetes used 2,400 mg/day for 12 weeks (2.4 g) ^[4], dose-escalation studies and acceptability work tested 1–4 g/day or 2.4–7.2 g/day ^{[2] [1]}, and single-meal studies added 20 g or 50 g of leaf powder to food in acute experiments ^{[1] [5]}. None of the cited clinical papers or reviews in the provided set identify trials that specifically tested single or daily doses below 500 mg of moringa leaf extract in humans; the literature repeatedly characterizes trial dosing in the hundreds of milligrams to multiple grams, often emphasizing gram-level exposures ^{[1] [2] [3]}.

2. Reported adverse events in human trials — rare and generally mild

Across the clinical literature summarized in the reviews, moringa preparations have been described as “well tolerated” with few adverse effects: randomized and small clinical studies reported no significant changes in routine lab values (including liver enzymes) and often explicitly stated no adverse effects were observed ^{[3] [5] [2]}. The acceptability trial noted more self‑reported gastrointestinal symptoms in the highest dose group (≈7.2 g/day) compared with the lowest (≈2.4 g/day), indicating GI complaints are the principal, dose-related adverse observations in human studies ^{[1] [6]}. Drug information summaries and clinical reviews likewise list occasional diarrhea or GI upset among the few reported events and otherwise no consistent safety signal in trials ^{[4] [7]}.

3. Signals outside randomized trials and animal warnings that matter

Although clinical trials summarized here did not show major toxicity at the doses they tested, other sources raise cautions: animal studies report abortifacient and anti‑fertility effects at certain extract doses (reported in mg/kg in preclinical work), suggesting reproductive risks that have not been tested in controlled human trials ^[8]. A recent hepatotoxicity report — a single clinical case of acute, anicteric hepatitis attributed to moringa in South America — appears in a case series and registries and is not mirrored in the small clinical trials that measured liver enzymes ^[3]. These outlier signals do not overturn the trial findings but do flag areas where trial data are limited and post‑marketing or case reports may detect rare harms ^{[3] [8]}.

4. Drug interactions, data gaps and interpretation caveats

Preclinical and interaction summaries note moringa components can inhibit CYP3A4 in vitro, with potential to alter concentrations of co‑administered drugs metabolized by that pathway — a mechanistic concern that has not been resolved by large clinical interaction trials in humans ^{[9] [10]}. Major systematic reviews and drug compendia underline that clinical evidence is limited in scale and quality: most published human studies use relatively large powder doses, report no serious adverse events, and sometimes fail to report side effects in detail ^{[5] [2] [4]}. Therefore the strongest, evidence-based conclusion supported by the provided material is negative on sub-500 mg human trial data (no trials identified), and broadly reassuring for the gram-level doses tested, with mild GI effects the most reproducible complaint and rare case reports raising isolated safety questions that require further investigation ^{[1] [6] [3]}.