Everything You Should Know About Neem

Neem (Azadirachta indica) is a type of tree indigenous to India that is used in alternative medicine to prevent gum disease and treat head lice. Neem oil is also used as a pesticide.

Neem is available as a capsule, powder, oil, tincture, cream, or mouthwash. Some remedies are made from the bark, flowers, or fruit of the neem tree.

This article discusses the purported uses of neem, its side effects, and the risks associated with taking neem supplements.

Neem powder

Image by Anastasia Tretiak for Verywell Health

Benefits and Uses of Neem

The purported health-friendly properties of Neem are numerous and have led to it being used as an antioxidant and for antifungal, antibacterial, and pest control applications. It's also used to reduce inflammation and boost the immune system.

Research on the potential health benefits of neem is limited. While neem has been studied in lab and nonhuman animal studies for potential uses (cancer, diabetes, stomach ulcers, and malaria among them), there is not enough evidence to support its use due to lack of human research.

More research is needed with well-designed, placebo-controlled, peer-reviewed human research studies.

Dental Health

A few studies have evaluated whether neem can help fight the plaque buildup on teeth and prevent a gum disease called gingivitis. However, the results are mixed.

A 2017 randomized, double-blinded study in the Journal of Contemporary Dental Practices reported that neem mouthwash was as effective as commercial mouthwashes containing chlorhexidine gluconate, a substance commonly used to prevent gum disease. However, the study was small, involving only 40 people for one week.

A more extensive review of studies published in 2017 in the International Journal of Dental Hygiene did not reach the same conclusions. The researchers could find no evidence that neem mouthwash is a reasonable alternative to chlorhexidine mouthwash.

Insect Repellant

A limonoid (plant chemical) compound in neem seeds called azadirachtin has toxic effects on insects. They include fleas on cats and dogs, cattle ticks, and more. Neem products also are used as pesticides.

There's some indication neem can be used in treating malaria, a mosquito-transmitted disease, but more research is needed. A number of neem studies show promise in general mosquito control, including products like neem-oil-infused nanofiber mats tested for mosquito prevention.

Lice

Neem seed extract shampoo has been found to be effective in ridding head lice, and neem remains one of the most common herbal treatments for lice.

A 2017 study of 134 people found that when neem oil was added to a silicone solution, it led to a cure in 72% of those treated with it. The silicone made it more effective, and also made it smoother and easier to comb out nits (lice eggs), raising the rate to 82% with added combing.

Unproven Uses

Neem products have been studied for their benefits in a host of conditions that require more research evidence to support their effectiveness and safety. These conditions include:

What Are the Side Effects of Neem?

Consuming a supplement like neem may have potential side effects. These side effects may be common or severe. Due to lack of research, little is known about the safety of short-term or long-term use of neem; however, there are some possible concerns and side effects.

Topical use (placed on skin) can cause:

Neem oil should not be consumed orally.

Oral consumption can lead to:

Who Should Not Take Neem?

People who are pregnant or lactating should not use neem supplements due to the lack of safety research in those groups. Consuming neem oil is not advised, even at low doses. Poisoning has occurred in both children (even in low doses) and adults, with reports of severe impacts in infants.

Dosage: How Much Neem Should I Use?

There is not enough scientific evidence to determine a standard or appropriate dose of neem. More research is needed on dosages for specific health needs and populations, though one study of neem oil put the dosage limit at 1600 milligrams (mg) per kilogram (kg), per day, for no more than 90 days.

Other studies (animal and human) have identified:

  • An average dose of 10 mg/kg of body weight for fighting cancer
  • A high dose of 120 mg/kg for limiting pain caused by inflammation (in rats)
  • A dose of 2 milliliters per kg of seed oil extract had effects in limiting edema (swelling)
  • Neem extracts at 800 mg/kg may control blood sugar

Talk with your healthcare provider before you start taking neem or any supplement.

What Happens if I Take Too Much Neem?

Studies and research reports indicate a number of side effects and risks. In addition to warnings about its toxic effects in children and symptoms including lethal complications, neem can interact with certain liver enzymes.

As a rule of thumb, never take more neem than the manufacturer's recommended dosage. This is true for any of its forms. If you experience side effects, stop taking neem and call your healthcare provider.

Interactions

At this time, there is limited information regarding known interactions with different medications because of limited human research. Studies suggest that neem has blood sugar lowering effects. Therefore, taking neem with diabetes medications, such as metformin, could cause blood sugar to drop too low.

The use of some CYP450 substrate medications can be affected by this interaction because of effects on liver enzymes.

Talk to your healthcare provider before starting neem or any other supplement to determine whether it is safe to take with your current medications.

Sources of Neem and What to Look For

Neem can be found online and in many dietary supplements or natural food stores. It comes in many forms, including capsules, tinctures, powders, oil, creams, shampoos, and mouthwashes.

Are Neem Products Regulated?

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Choose a supplement tested by a trusted third party, such as U.S. Pharmacopeia (USP)ConsumerLab.com, or NSF.org, whenever possible. However, even if supplements are third-party tested, they are not necessarily safe for all or effective in general. Therefore, talking to your healthcare provider about any supplements you plan to take and asking about potential interactions with other supplements or medications is essential.

Summary

Neem has been traditionally used to treat a wide range of health conditions, including head lice and dental issues like gingivitis. However, most claims are not backed by enough human data and require more research. Neem is available as a capsule, powder, oil, tincture, cream, or mouthwash.

Just like with any other supplement, consult with your healthcare provider first if you are thinking about taking neem.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  6. Konchada S, Killi N, Sayyad S, Gathalkar GB, Gundloori RVN. Blends of neem oil based polyesteramide as nanofiber mats to control Culicidae. RSC Adv. 2020 Nov 25;10(70):42827-42837. doi: 10.1039/d0ra08297j.

  7. Burgess IF, Brunton ER, Burgess NA, Burgess MN. Neem-silicone lotion and ultrasound nit comb: a randomised, controlled clinical trial treating head louse infestationBiomed Dermatol 1, 8 (2017). doi: 0.1186/s41702-017-0009-0

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Alena Clark

By Alena Clark, PhD
Alena Clark, PhD, is a registered dietitian and experienced nutrition and health educator

Originally written by Cathy Wong