Neem oil is a pungent, yellow-brown oil found in the seeds of the neem tree, which originated in India. It is often used as an alternative to synthetic, chemical-based insect repellents and head lice treatments. Neem oil also contains compounds with potential antiinflammatory properties, which may help relieve symptoms of some skin conditions. However, undiluted neem oil is potent and may irritate your skin or scalp. Diluting it in a carrier oil, lotion or shampoo before applying it to your skin or hair delivers the benefits of neem oil while minimizing the risk of irritation.
Neem oil contains a compound called azadirachtin, which repels insects such as mosquitoes, ticks, fleas and ants. Various products from the neem tree are used for insect control in organic farming because of these properties. The authors of an October 2013 review article published in the "Asian Pacific Journal of Tropical Biomedicine" report that a small field study conducted in India demonstrates that diluted neem oil offered significant protection against mosquito bites for up to 12 hours. To make your own insect repellent, mix 2 mL of neem oil into 100 mL of a carrier oil, such as coconut or olive oil. Rub the mixture in a thin layer on exposed skin. Reapply at least every 12 hours.
Like other oils, neem oil acts as a skin moisturizer. This property along with its potential antiinflammatory properties may help relieve symptoms of skin conditions exacerbated by dryness, such as eczema and psoriasis. The authors of a laboratory-based study published in the May 2004 issue of "Phytotherapy Research" report that applying nimbidin -- the major active ingredient in neem oil -- to immune system cells isolated from rats inhibited functions that increase inflammation. Although these effects of nimbidin have not been verified in humans, they suggest neem oil may have antiinflammatory properties that could potentially prove beneficial for the treatment of inflammatory skin conditions. However, additional research is need to confirm this speculation. Although adding neem oil to your favorite lotion may enhance its moisturizing effects, a high concentration of neem oil may further irritate sensitive skin. Start with a low concentration of neem oil, such as 1 mL of neem oil to 100 mL of lotion. Apply it to a small area of affected skin to test for irritation. You can try small increases in the neem oil if you don't notice any improvement in symptoms and do not experience additional irritation.
Neem oil interferes with the feeding and reproduction of many insects. Although neem oil is not among the treatments recommended by the Centers for Disease Contol and Prevention or the American Academy of Pediatrics, some people choose neem oil rather than over-the-counter or prescription medicines for the treatment of head lice. If you decide to try neem oil to treat head lice, you may need a relatively high concentration, such as 5 mL of neem oil to 100 mL of shampoo. Apply at least 20 to 30 mL of the oil-containing shampoo to the hair and leave it in for at least 10 minutes. If the lice remain, talk with your doctor about your next steps.
Some people may be sensitive to neem oil, especially at high concentrations. Therefore, always test your neem oil-based solution by applying the concentration to a small area of your skin or scalp before applying it across a larger area. Although neem oil is generally safe for external use, ingesting high concentrations of neem oil is generally not advised because it may influence hormone production. If you have preexisting medical conditions, check with a health-care professional before using neem oil.