Neem In Research

In 1992, a group of U.S. government agencies including the National Academy Press, the U.S. Agency for International Development, the National Research Council, the National Academy of Sciences, the Institutes of Medicine and the U.S. Department of Agriculture as well as the Board on Science and Technology for International Development, published a book entitled “Neem: A Tree for Solving Global Problems.”

Still available online, the book notes that neem has been used through the centuries to treat a myriad of disorders with part of the forward reading:

“To those millions in India neem has miraculous powers, and now scientists around the world are beginning to think they may be right. Two decades of research have revealed promising results in so many disciplines that this obscure species may be of enormous benefit to countries both rich and poor. Even some of the most cautious researchers are saying that “neem deserves to be called a wonder plant.”

Since its publication 15 years ago, an enormous amount of research has been completed in laboratories and universities around the world. We’ll be the first to admit that modern research hasn’t always supported neem’s “healer of all ailments” moniker. Still, considering the wide variety of disorders where researchers can detail positive results – combined with the fact that it has few side effects – results of this ongoing research probably surpass the expectations of the people who called it a wonder tree 15 years ago.

Beyond “Solving Global Problems”

From the perspective of poor countries in tropical growing zones, neem offers multiple benefits. Easily grown in poor, dry soil, it’s the ideal tree for reforestation. It’s so tenacious, in fact, that the tree can be cut down for firewood or fencing while the roots continue to hold soil in place and send up new growth. Both leaves and oil pressed from abundant seeds can be used on crops with minimum impact on people, wildlife or beneficial insects.

Closer to home, neem is being recognized more for its medicinal qualities. Ongoing research, detailed at the National Institutes of Health’s Library of Medicine website, shows significant potential in treating disorders as diverse as AIDS, cancer, ulcers, arthritis and diabetes. Just as the diseases are different, the varied compounds in neem have multiple mechanisms. In many cases, it’s clear that neem’s immune-boosting properties play a critical role. Selective toxicity to insects, cancer cells, parasites (particularly malaria), fungus and bacteria is important in other instances.

Separate reports on each of these topics provide the latest information from the NIH site, along with a brief overview that explains the basic concepts. But while neem has been in continual use for thousands of years, it is a potent herb. Please read our section on safety before starting any program using neem.

  • Antibacterial Compounds in Neem – Ongoing research over the past 45 years recognizes these traditional uses of neem, but researchers typically list them as “known to be” rather than reporting on their action. More recent reports focus on antibacterial activities in the mouth, specifically gum disease and cavities, as well as preventing sexually transmitted diseases as a vaginal contraceptive.
  • Antifungal Properties of Neem – Like neem’s antibacterial and antiviral properties, its antifungal properties are often a given among scientists in India and other Asian nations where most of the current research is being conducted. Reports completed before 1992 are not available online but do indicate that compounds in neem help control fungi that can cause athlete’s foot, ringworm and candida, the organism that causes yeast infections and thrush, as well as fungus that may affect plants. *
  • Anti-Inflammatory & Neem – Nimbidin, a component of neem, has been show to posses potent anti-inflammatory and antiarthritis activity in both in vivo and in vitro settings. Researchers suggest that nimbiden suppresses the functions of macrophages and neutrophils involved in inflammation. Earlier research not available online also documented neem’s anti-inflammatory properties.
  • Antioxidant Compounds in Neem – Oxidative stress, the process through which free radicals are created, is a normal function of the body but the resulting molecules are unstable and can damage other cells. Researchers have associated a series of disorders, including cardiovascular disease, eye health, cataracts and macular degeneration, age-related neurodegeneration (decline of the brain and nervous system) and even cancer with high levels of free radicals. Antioxidants, including those found in vitamins A, C and E, provide the free radicals with electrons to minimize damage. More than a dozen studies conducted in India, Thailand and Malaysia indicate that neem protects against chemically induced carcinogens and liver damage by boosting antioxidant levels, particularly glutathione.
  • Antiviral Compounds in Neem – Other researchers report that neem inhibits the growth of Dengue virus, a hemorrhagic fever related to Ebola, and interferes with the reproduction of the coxsackie B virus, one of a group of “enteroviruses” that are second only to the common cold as the most infectious viral agents in human beings.
  • Cancer & Neem – More than two dozen studies, both in test tubes and on animals, document neem’s efficacy in killing cancer cells or boosting the body’s immune system to protect it from damage. Neem or its isolated compounds have shown impressive action against a wide variety of human cancer cell lines and in animal models for cancers that include colon, stomach, Ehrlich’s carcinoma, lung, liver, skin, oral, prostate and breast cancers. Two separate reports indicate that it may be helpful in enhancing the activity and reducing side effects of some conventional cancer treatments.
  • Potential Contraceptive Properties of Neem – From the perspective of developing countries – or any woman concerned about the long-term impact of using hormones for birth control — finding a method of contraception that is effective, inexpensive and easily available is truly a step toward solving global problems. Reports from the University of Florida encourage ongoing research into the use of neem as either a pre- or postcoital contraceptive, noting that it prevented in vitro attachment and proliferation of cells in concentrations as low as .05 to 1%. Another report in the American Journal of Reproduction indicates that purified extracts of neem contained immunomodulators that stimulate Th1 cells and macrophages that terminate pregnancies in rats, baboons and monkeys. Fertility was regained after one or two cycles with no apparent impact to future pregnancies.
  • Diabetes & Neem – With its extremely bitter properties, neem has been a cornerstone of Ayurvedic therapy for pitas, or disorders caused by overeating sweets. Some of the earliest reports on neem, dating back to a 1973 report in Medicine and Surgery (not available online), indicated that insulin requirements could be cut. More recent studies have focused on animals, including one report which indicates that neem’s hypoglycemic effect is comparable to the prescription drug glibenclamide and noted that it may be beneficial in preventing or delaying the onset of disease.
  • Immunostimulatory Compounds In Neem – Until we compiled the data on neem and cancer, we thought its immunostimulating properties were neem’s most important benefits. It’s such a powerful booster than some researchers have attributed its contraceptive properties – for both men and women – to an enhanced immune system. It boosts both the lymphocytic and cell-mediated systems, including “Killer T” cells which are able to destroy microbes, viruses and cancer cells by injecting toxic chemicals into the invaders.
  • The Liver & Neem – Throughout its long history, neem has often been recommended as blood cleanser. The truth of the matter may be it that helps protect the liver from damage, which in turn helps cleanse blood. The details are extremely complex (available online), but the research indicates that neem leaf appears to minimize chemically induced liver damage in rats by stabilizing levels of serum marker enzymes and boosting levels of antioxidants, like those found vitamins C and E and other natural carotenoids, which neutralize free radicals and help prevent damage. Several studies indicate that neem provides significant protection for the livers of rats who have been fed large doses of acetaminophen.
  • Malaria & Neem – While questions still remain about the dosage required in human beings, neem clearly has great potential in preventing malaria, a parasite that kills more than a million people per year. Several in vitro studies indicate significant protection, including one that concluded it was more effective than chloroquine, a drug to which the parasite is becoming resistant. One interesting report indicates that it may increase the efficacy of chloroquine when the two are taken together.
  • Neuroprotective Effect of Neem – A single study shows that indicates that antioxidant compounds in neem helped to prevent brain damage in rats who had suffered a stroke by enhancing lipid peroxidation and increasing ascorbic acid (Vitamin C) in the brain. Rats pre-treated with neem seemed to complete standard tests, including a water maze, better than the control group and blood parameters were significantly improved over the untreated rats.
  • Oral Disease & Neem – Another traditional use of neem has been chew sticks still used to clean teeth in rural parts of India and Africa (and the US more recently). A series of studies confirm that has antimicrobial properties that help reduce plaque and gingivitis.
  • Safety Issues & Neem – When used as directed, neem leaf and bark show very few signs of toxicity even at high levels. Neem oil, however, should not be used internally. High levels of neem (up to 320 grams per kilogram in rats) taken internally may result in damage to the thyroid, liver, and kidneys, although the organs showed significant recovery after 28 days. Neem also contains compounds similar to aspirin and should never be used in children with colds, fevers or flu.
  • Sexually Transmitted Diseases & Neem – Another area where neem shows great potential is sexually transmitted diseases. One study funded through an agency of the US government found that neem provided 75% protection from the HIV virus to cells in a test tube and volunteers with AIDS who took neem for 30 days gained an average of three kilograms. Key chemical markers, including CD4+ cell counts, hemoglobin and platelet counts, also increased. A 1997 study at Johns Hopkins University also showed that neem provided significant protection against the herpes virus in mice.
  • Stress & Neem – A small number of animal studies indicate that low doses of neem leaf extracts have sedative effects comparable to those in diazepam – the active ingredient in Valium. Interestingly enough, that effect disappears at high doses, approximately 400 or 800 milligrams per kilograms of body weight.
  • Ulcers & Neem – One of the few recent clinical trials among humans using neem indicates that neem bark causes significant decreases in gastric acid secretion (77%), as well as gastric secretion volume (63%) and pepsin activity (50%) That research may be particularly important for people with arthritis or other chronic pain. Along with its own anti-inflammatory compounds, neem may help counteract the gastric damage caused by pain relievers like aspirin and ibuprofen.

Most of this research data was compiled from the National Institutes of Health website and is presented here as a public service to customers. Using Neem does not sell products which are intended to diagnose, treat, cure or prevent any disease, or repel or kill any insect on humans, animals or plants. The research presented on this page is not intended to diagnose, treat, cure or prevent any disease. The statements have not been evaluated by the U.S. Food and Drug Administration. Whenever possible, links to abstracts published by the National Institutes of Health (a division of the U.S. Department of Health and Human Services) are provided. However, some of the earlier research is not available online and appropriate footnotes have been provided.

Most of this research data was compiled from the National Library of Medicine at the National Institutes of Health website ( and is presented here as a service to visitors. Using Neem does not sell products which are intended to diagnose, treat, cure or prevent any disease, or repel or kill any insect on humans, animals or plants.

%d bloggers like this: