Neem Oil: Uses, How to Use It, and Safety (Aceite de Neem)

Never give neem oil by mouth, especially to infants or children, and keep the bottle out of their reach. Avoid it if you are pregnant or trying to conceive, and do not use it on cats.

What is neem oil?

Neem is an evergreen tree native to India and Sri Lanka, and every part of it (bark, leaves, flowers and seeds) has a place in South Asian traditional medicine (MSKCC). Neem oil comes specifically from the seed kernels. The Now neem oil we carry, for example, is cold-pressed without solvents. The oil ranges from yellow to brown in color. It has a bitter taste and a smell many people compare to garlic or onions (National Pesticide Information Center, NPIC).

Chemically, it is a mix of ordinary plant fats and a long list of bitter compounds. Free fatty acids, including oleic, stearic and palmitic acids, account for roughly a fifth of its weight (LiverTox). The bitter part includes limonoids such as azadirachtin, nimbin, nimbidin and salannin. Researchers have counted at least 100 biologically active compounds in neem oil, and azadirachtin is the one most responsible for its effect on insects (Campos et al., Frontiers in Plant Science, 2016). LiverTox, the NIH database on drug-induced liver injury, also notes that the bitter compounds develop during storage, so their levels differ from one bottle to the next.

Neem oil tends to turn solid in a cool room. That is normal: set the bottle in warm water for a few minutes and it will liquefy again.

What is neem oil used for? (¿Para qué sirve el aceite de neem?)

Most uses fall into three groups: skin and hair care, head lice, and plant protection. Here is what each one rests on.

Skin and scalp. In Ayurveda, neem has long been applied to the skin, and modern cosmetic makers add neem oil to soaps, lotions and creams (MSKCC; NPIC). Lab studies show neem extracts can act against a range of microbes, but good human trials on everyday skin complaints are scarce. One small clinical report described a neem oil solution that helped skin ulcers heal in people with systemic sclerosis, without whole-body side effects (Giuggioli et al., 2019, as summarized by LiverTox). That is encouraging, but it is a narrow medical setting, not proof that neem oil clears acne or dandruff. Think of neem oil as a traditional skin oil with limited evidence, not as a treatment.

Head lice. Neem seed extract is the active ingredient in some lice shampoos, including the one tested in these studies. In an Egyptian study, 60 children aged 4 to 15 with heavy infestations were treated once with a neem seed extract shampoo, and the researchers reported it worked against all life stages of lice with no scalp irritation (Abdel-Ghaffar and Semmler, Parasitology Research, 2007). A follow-up with 20 children found no surviving lice after a 10 or 20 minute application, and no live lice a week later (Abdel-Ghaffar et al., 2012). Both studies were small and had no comparison group, and they used a finished shampoo, not plain oil. If you want to try neem for lice, talk with your pediatrician first and keep it away from the eyes.

Garden pests. This is the use with the strongest regulatory backing. Neem oil and purified parts of it appear in over 100 registered pesticide products, used on crops and ornamental plants (NPIC). Azadirachtin discourages insects from feeding and disrupts the hormones they need to grow and lay eggs. When azadirachtin is pulled out of the oil, what remains is sold as clarified hydrophobic neem oil. Other compounds in the oil also make it hard for insects to feed. Azadirachtin breaks down quickly: its half-life on plant leaves is about one to two and a half days. Bees and other pollinators are unlikely to be harmed because insects have to eat treated plant tissue to be affected, but azadirachtin is moderately toxic to fish, so keep spray out of ponds and streams (NPIC). For the garden, buy a product labeled as a pesticide and follow its directions.

Why you should never drink neem oil

Neem oil is meant for the outside of the body. Taken by mouth, it has caused serious harm.

• In Malaysia, 13 infants became drowsy, vomited and developed metabolic acidosis and encephalopathy (a serious disturbance of brain function) within hours of being given margosa oil (another name for neem oil). Doctors linked it to a Reye-like syndrome, with fatty changes in the liver (Sinniah and Baskaran, The Lancet, 1981).
• A 4-month-old given a second dose for a cough died about ten days later (Sinniah et al., 1982, summarized by LiverTox).
• A previously healthy 5-year-old in India had seizures that were hard to control after swallowing neem oil, and was left with hearing, vision and balance problems (Dhongade et al., Indian Pediatrics, 2008).

LiverTox rates neem oil as a probable but rare cause of liver injury, and suggests contamination may explain some outbreaks. Memorial Sloan Kettering adds that poisoning from swallowed neem oil has been reported in adults as well as children. The safe rule is simple: no neem oil in food, drinks or home remedies taken by mouth, and store it like any other product that could hurt a curious child.

Pregnancy and fertility. In animal research, neem oil has ended pregnancies in rats (NPIC) and has been studied as a contraceptive (Lal et al., Indian Journal of Medical Research, 1986). There is no good human safety data, so skip neem products if you are pregnant, breastfeeding or trying to conceive.

Pets. Cats treated with neem oil for fleas have had drooling, trembling, seizures and, in some cases, died (NPIC). Do not use it on cats.

Skin reactions. Allergic and irritant dermatitis from neem oil are documented, including a case of rash on the scalp and face in someone using it for hair loss (MSKCC).

How to dilute neem oil for skin and hair

Pure neem oil is strong and smelly, so it is almost always mixed with something else before it touches skin. The Neem Aura seed oil we carry is labeled for external use only, with directions to add a few drops to a carrier oil, shampoo or lotion.

• Pick a carrier. A mild oil such as jojoba, coconut or sesame works well. See our guide to cold-pressed oils for options.
• Start small. Follow the label and begin with just a few drops in your carrier. Neem is strong, and more is not better.
• Patch test. Dab the mix on the inside of your forearm and wait a day or two. Redness, itching or bumps mean neem oil is not for you.
• For the scalp. Stir a few drops into a palmful of your usual shampoo, or into a carrier oil for a pre-wash scalp treatment. You can also blend it into a thicker oil such as Jamaican black castor oil.
• Keep it off the face at first. Try it on the body before using it near the eyes, and rinse well if it gets in them.

Neem oil vs neem leaf: the forms of neem compared

Neem oil and neem leaf are not interchangeable. The oil comes from the seeds and is used on the outside of the body. The leaves are dried for powders, teas and capsules, and are also extracted into creams. For more on the leaf, see our neem leaf guide.

Find it at William's

We carry several neem products, each suited to a different job:

• Now neem oil, 1 fl oz: cold-pressed, solvent-free oil from wild-harvested neem seeds, for diluting into skin and hair care.
• Neem Aura Naturals neem seed topical oil, 1 oz: certified organic neem seed oil, labeled for external use and meant to be added by the drop to a carrier oil, shampoo or lotion.
• Neem Aura concentrated neem cream, 2 oz: neem leaf extracted into an aloe vera base with other herbs, for anyone who wants neem on the skin without measuring and mixing oil.
• Solaray Neem 460 mg, 100 veg capsules: a dietary supplement, not a substitute for the oil. Read the label and check with your clinician before taking it.

Our neem oils are sold for personal care, not as garden pesticides. If you are curious how neem fits into Ayurveda more broadly, our Ayurveda basics guide is a good next read.

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