Know2eat

Neem

Azadirachta indica

Herbs & Botanicals

What neem may help with

Ranked by how strong the human evidence is — best supported first.

Best supportedBlood glucose responseNot enough evidence· 1 source

Then, in order

About Neem

Leaf, bark, seed and oil preparations from the neem tree, long used in Ayurveda and as an agricultural insecticide. Neem oil is pressed from the seed and contains azadirachtin and related limonoids.

Neem is the rare botanical where the strongest human data concern harm rather than benefit: neem oil poisoning in children is a documented cause of encephalopathy and death in South Asia. Oral leaf preparations have some small trials in dental plaque and glycaemia, none of them enough to build a conclusion on.

Sold as
Leaf capsule, Leaf powder, Neem oil (topical), Toothpaste and mouthwash, Bark extract
Also known as
Indian lilac, Nimba, Margosa

Regulation: Neem oil is registered as a pesticide in the US and EU. That is a different regulatory route from a supplement and does not imply any assessment of safety when swallowed.

What the research used

The amounts, forms and durations published trials of Neem actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

  • Studied for Dental plaque and gingivitis, topical

    2 mg/mL

    Limited

    Neem mouthwash or gel · 2–6 weeks

    Small dental trials, several without blinding. This is a rinse, not an oral dose.

  • Studied for Oral leaf preparations

    500–2000 mg

    Not enough

    Leaf powder or extract capsule

    Oral trial dosing is not well established for neem, and the margin between traditional leaf use and toxic seed-oil exposure is a serious practical issue.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

  • Any time

    Not enough

    No timing has been tested for neem in human studies.

    Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

The evidence in depth

Best supported: Not enough

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Blood glucose response

Blood Sugar & Metabolic Health
Not enough evidence

Evidence is limited for neem and blood glucose in people. A few small trials report reductions, but they are poorly controlled and have not been replicated.

Not enough evidence. Not enough human research to say anything useful yet.

View the 1 source

Deep research mode adds each paper’s own conclusion and stated limitations.

Digestive comfort

Gut & Digestive Health
Not enough evidence

There is not enough human research to say oral neem affects digestive symptoms. Most of its gastrointestinal reputation comes from traditional use and animal ulcer models.

Not enough evidence. Not enough human research to say anything useful yet.

View the 1 source

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

  • Worth knowing

    Neem oil is toxic to infants and children

    Swallowed neem oil has caused vomiting, drowsiness, seizures, encephalopathy and death in infants and young children, with cases documented across South Asia. Neem oil should never be given internally to a child.

  • Avoid

    Pregnancy and fertility

    Neem seed extracts have documented abortifacient and spermicidal activity, and have been investigated as contraceptives. They should not be used in pregnancy or by couples trying to conceive.

  • Interaction

    Glucose-lowering and immunosuppressant drugs

    Interacts withInsulin, sulfonylureas, immunosuppressants

    Neem may add to the effect of antidiabetic medication, and its immune-stimulating activity makes it a poor combination with immunosuppressants.

  • Worth knowing

    Liver and kidney effects at high intake

    Case reports link large or prolonged neem intake to liver and kidney injury, and animal studies show hepatotoxicity at high doses.

  • Worth knowing

    Ayurvedic sourcing and heavy metals

    Imported Ayurvedic products have repeatedly been found to contain lead, mercury or arsenic, sometimes at levels causing clinical poisoning.

Evidence ratings on this page: 2 not enough evidence.

Supplements are sold in the US without pre-market review of efficacy or safety. Nothing on this page is a recommendation to take Neem, or a dose to follow.