Neem Oil: The Natural Insect Repellent

Warm summer nights in the backyard, serene hikes along a creek, idyllic picnics at the lake—all moments that can be ruined by the pesky presence of mosquitoes and other insects. If you’re looking for a natural alternative to traditional bug sprays, nature offers a defense in the form of Neem. 

Derived from the seeds, bark, or leaves of the Neem tree, Neem oil is a natural insect repellent revered for centuries for its wide range of potential health benefits. Let's explore this ancient herb and why it may be a valuable addition to your summer arsenal.

The Sacred Neem Tree

The Neem tree (Azadirachta indica), native to the Indian subcontinent, has been used in Ayurveda, the traditional Indian system of medicine, since at least 2,000 BCE. In Ayurveda, Neem is classified as a bitter and cooling herb and is believed to balance the three doshas — the energies thought to be responsible for one’s physical, mental, and emotional health. 

Neem, a drought-resistant evergreen and botanical cousin of the mahogany tree, is one of the most widely planted trees in India, found along roadways, in front of people’s homes, and in graveyards. It’s not only popular in India for its insect-repellent properties, but it is also thought to ward off evil spirits. It is so deeply woven into Hindu rituals and folklore that its leaves and flowers are often made into garlands and wrapped around deities.

The Neem tree is now cultivated and naturalized in many other tropical and subtropical regions around the world, including Florida, Texas, and Southern California in the United States. 

Traditional Uses of Neem

Every part of the Neem tree is considered to have value in Ayurveda. Flowers, leaves, bark, seeds, and oil are all used for different purposes. Even the twigs of the tree are chewed by many Indians to clean their teeth. 

Some common traditional uses of neem include:

• Skin Support: Neem has been used to support the skin and is often applied topically in the form of poultices, pastes, or oil.
• Digestive Health: Neem leaves and bark have been used to support digestive health and alleviate issues like occasional indigestion, occasional bloating, and occasional constipation.
• Oral Health: Chewing on neem twigs is believed to promote oral hygiene.

The traditional use of Neem has extended beyond India to other countries in South Asia, Southeast Asia, Africa, and the Middle East, where it has been adopted to support one’s health.

Scientists have identified over 300 bioactive compounds in the Neem tree, many of which, when isolated, offer a wide range of beneficial biological activities that may support overall health.REF#2700 

The number of human studies that have been done on the leaves, seeds, bark, and flowers of the Neem tree is limited. Initial results are promising, but more research is needed to fully understand Neem's health effects, optimal dosing, and long-term safety before it can be recommended for its traditional uses. 

Neem Oil as an Insect Repellant

One of Neem oil’s most obvious and researched features is its ability to repel biting insects. Neem oil breaks down quickly in the environment without the same health and environmental risks as synthetic repellents.REF#2704 It is believed to work through multiple active compounds that alter insect behavior. The key component, azadirachtin, a limonoid, can deter biting insects through its unpleasant taste and smell. By inhibiting molting, azadirachtin also keeps insect larvae from developing into pupae and producing a new generation. 

While azadirachtin is responsible for most of Neem oil's insecticidal and insect-repellent properties, Neem has a complex mixture of bioactive compounds that may work together to provide insect-repelling effects. These additional compounds include nimbin, salannin, nimbolide, and meliantriol. 

Studies have found that Neem-based repellents provide safe and low-risk protection against mosquitoes comparable to DEET products. While DEET, a controversial chemical used in commercial insect sprays, lasts up to 8 hours, Neem was found to be effective for up to 3 hours. REF#2701

In animal studies, Neem oil has also proven effective in killing tick larvae and may be effective in killing adult ticks on contact.REF#2702 REF#2703 REF#2705 Additionally, a Neem extract-containing shampoo has been shown to be effective at treating head lice when left in the hair for 10 to 20 minutes. REF#2706

Commercial Neem repellents are made from the seeds or leaves of the Neem tree, which are crushed and steeped in water, alcohol, or other solvents. They come in the form of extracts, sprays, and granules.

How to Make Your Own Neem Oil Repellent or Lice Treatment

When you make your own Neem oil repellent, you control the quality of the ingredients that go in it. You can also adjust its strength based on how it works to ward off or kill biting insects around you.

We recommend you start with a 100% raw, organic, cold-pressed Neem seed extract or Neem seed essential oil to serve as your base. This gives you the assurance that the main active compound, azadirachtin, is stable and free of contaminants.

Instructions for Neem Oil Insect Repellent

You can make Neem oil insect repellent as an oil or spray. 

For a repellent oil, combine:

• 4 tablespoons Neem seed oil 
• 4 tablespoons coconut or olive oil 

1. Apply several drops of the mixture on exposed areas of skin and rub in gently. 
2. Store in a dark glass dropper bottle at room temperature. 

For a repellent spray, combine:

• 1 teaspoon Neem seed oil
• ½ teaspoon liquid soap
• 4 cups filtered or distilled water

1. Store in an opaque spray bottle at room temperature.
2. Spray on skin as needed.

Instructions for Neem Oil Lice Treatment 

You can treat head lice and nits by mixing one part Neem seed oil with two parts carrier oil. Mix together the following ingredients, adjusting quantities based on the amount of hair:

• 4 tablespoon Neem seed oil
• 8 tablespoons coconut or olive oil

1. Rub liberally into hair and scalp.
2. Cover hair with shower cap and leave mixture on for 20 minutes. 
3. Rinse thoroughly and comb hair with a nit comb, removing dead nits from the comb by immersing them in a bowl of boiling water. 
4. Wash hair with your own shampoo and rinse. Follow with your own conditioner if desired.

If one treatment does not kill all lice, repeat the process daily until they are all gone. 

Neem Oil Side Effects and Precautions

Neem products have been tested over time on warm-blooded animals and have had little or no toxicity, but, there is limited human clinical research on Neem’s safety and dosage recommendations. The known compounds in the oil are generally recognized as safe (GRAS) by the United States Food and Drug Administration. 

There is little evidence that when Neem oil is used topically, it has any major side effects. However, to be completely safe, use it with the proper dilution of Neem oil to carrier oil and patch test it on a small area of skin to check for allergic reactions. 

There have been rare case reports of Neem oil poisoning when it has been ingested in excess. Small oral doses may be safe when taken for short periods. Consult with a healthcare provider before taking Neem oil orally.

Possible side effects of Neem oil usage may include:

• Skin irritation: Applying undiluted Neem oil directly on the skin may cause irritation, redness, itching, or a rash, especially if you have sensitive skin. 
• Eye irritation: Undiluted neem oil can irritate mucus membranes, including the eyes.
• Allergic reactions: If you are allergic to Neem oil, you may experience symptoms like swelling, hives, difficulty breathing, or anaphylaxis in severe cases.
• Gastrointestinal disturbances: Ingesting Neem oil or excessive consumption of neem-based products can lead to nausea, vomiting, diarrhea, or stomach upset.
• Hormonal imbalance: Neem oil contains compounds that can have hormonal effects, especially on the endocrine system. Long-term, high-dose usage may interfere with hormone regulation.
• Liver toxicity: Ingesting large quantities of Neem oil over an extended period can potentially lead to liver toxicity. 

Topical use of neem oil is not recommended for infants, children, or pregnant and breastfeeding individuals due to the lack of safety data. 

Regardless of your current health status, always consult a healthcare provider before using Neem oil orally to ensure you use an appropriate dilution and dosage. Neem oil may interact with certain medications, especially immunosuppressants, diabetes medications, and drugs metabolized by the liver.