Overview

Neem (Azadirachta indica) is a tree that grows in tropical regions such as India. The leaf extract is used to reduce tooth plaque and to treat lice.

Neem contains chemicals that might help reduce blood sugar levels, heal ulcers in the digestive tract, prevent pregnancy, kill bacteria, and prevent plaque from forming in the mouth.

People use neem for lice, tooth plaque, gingivitis, psoriasis, to repel insects, and for many other purposes, but there is no good scientific evidence to support most of these uses. There is also no good evidence to support using neem for COVID-19. Neem seed oil is used as a pesticide.

Uses & Effectiveness

Possibly Effective for

  • Tooth plaque. Applying a gel containing neem leaf extract to the teeth or using a neem mouthwash can reduce the amount of plaque on the teeth. But it is not clear if neem is as helpful as using chlorhexidine mouthwash or gel.
  • A mild form of gum disease (gingivitis). Applying a gel containing neem leaf extract to the teeth or using a neem mouthwash can reduce gingivitis in some people. But it is not clear if neem is as helpful as using chlorhexidine mouthwash or gel.
  • Lice. Applying a neem extract shampoo to the scalp once can treat head lice in children.

There is interest in using neem for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: Neem bark extract is possibly safe for most adults when used short-term. Doses of up to 60 mg daily for up to 10 weeks have been used safely. Neem is possibly unsafe when taken by mouth in large doses or for long periods of time. It might harm the kidneys and liver.

When applied to the skin: Neem oil or cream is possibly safe when applied to the skin for up to 2 weeks.

When applied inside the mouth: Neem leaf extract gel is possibly safe when applied inside the mouth for up to 6 weeks.

Special Precautions and Warnings

When taken by mouth: Neem bark extract is possibly safe for most adults when used short-term. Doses of up to 60 mg daily for up to 10 weeks have been used safely. Neem is possibly unsafe when taken by mouth in large doses or for long periods of time. It might harm the kidneys and liver.

When applied to the skin: Neem oil or cream is possibly safe when applied to the skin for up to 2 weeks.

When applied inside the mouth: Neem leaf extract gel is possibly safe when applied inside the mouth for up to 6 weeks.

Pregnancy: Neem oil and neem bark are likely unsafe when taken by mouth during pregnancy. They can cause a miscarriage.

Breast-feeding: There isn't enough reliable information to know if neem is safe to use when breast-feeding. Stay on the safe side and avoid use.

Children: Neem extract shampoo is possibly safe in children when applied once or twice to the head for 10 minutes, then rinsed with warm water. Taking neem seeds and seed oil by mouth is likely unsafe in children. Serious side effects in infants and small children can happen within hours after taking neem oil. These serious side effects include vomiting, diarrhea, drowsiness, seizures, loss of consciousness, coma, and death.

"Auto-immune diseases" such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), or other conditions: Neem might cause the immune system to become more active. This could increase the symptoms of auto-immune diseases. If you have one of these conditions, it's best to avoid using neem.

Reduced ability to have children (infertility): There is some evidence that neem can harm sperm. It might also reduce fertility in other ways. If you are trying to have children, avoid using neem.

Organ transplant: There is a concern that neem might decrease the effect of medications that are used to prevent organ rejection. Do not use neem if you have had an organ transplant.

Surgery: Neem might lower blood sugar levels. There is a concern that it might interfere with blood sugar control during and after surgery. Stop using neem at least 2 weeks before a scheduled surgery.

Interactions

    Moderate Interaction

    Be cautious with this combination

  • Medications for diabetes (Antidiabetes drugs) interacts with Neem

    Neem might lower blood sugar levels. Taking neem along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

  • Medications that decrease the immune system (Immunosuppressants) interacts with Neem

    Neem can increase the activity of the immune system. Some medications, such as those used after a transplant, decrease the activity of the immune system. Taking neem along with these medications might decrease the effects of these medications.

  • Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates) interacts with Neem

    Some medications are changed and broken down by the liver. Neem leaf might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Medications moved by pumps in cells (P-glycoprotein substrates) interacts with Neem

    Some medications are moved in and out of cells by pumps. Neem leaf might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.

  • Medications changed by the liver (Cytochrome P450 2C8 (CYP2C8) substrates) interacts with Neem

    Some medications are changed and broken down by the liver. Neem leaf might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates) interacts with Neem

    Some medications are changed and broken down by the liver. Neem leaf might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Dosing

Neem leaf, bark, and twig have been taken by mouth in adults. Neem creams, gels, and shampoos have also been used. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.
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CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is licensed from Therapeutic Research Center, LLC. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
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