Repellants, clothing, netting and other personal protection measures can help prevent mosquito bites and the diseases they carry. Insect repellants are effective, but not entirely safe — they must be used with caution. This page will help you choose a type of repellant and use it properly.

DEET Products

DEET (N,N-diethyl-3-methylbenzamide) is probably the best insect repellant. The chemical has been in public use since 1957.

Twenty years of testing of more than 20,000 other chemical compounds has not resulted in another product with the effectiveness and duration of protection of DEET. The repellant is sold under numerous brand names (Off ®, Cutter ®, etc.) and comes in lotion, spray and many other forms.

Concentrations of DEET range from about 5% all the way up to 100%. Generally, products with higher concentrations repel insects longer. After a certain point, though, higher concentrations do not guarantee greater protection. For example, 50% DEET provides about 4 hours of protection against mosquitoes, but increasing the concentration to 100% gives only about one extra hour of protection.

DEET must be used with proper precautions, however. The safe application of DEET is explained further below.

Other Recommended Products

Picaridin has effectiveness comparable that of DEET. Products with picardin can be expected to provide better and longer-lasting protection than plant-based repellents.

Oil of lemon eucalyptus has been tested against mosquitoes found in the US, and provides protection similar to repellents with low concentrations of DEET.

Plant-based Repellants

Repellants derived from plants such as citronella, geranium, basil, garlic and peppermint generally provide only temporary protection from mosquitoes, if any at all. A scientific study of Buzz Away ® (containing citronella, cedarwood, eucalyptus, and lemongrass) and Green Ban ® (citronella, cajuput, lavender, safrole-free sassafras, peppermint, bergaptene-free bergamot, calendula, soy and tea tree oils) showed essentially no effect against mosquitoes. Other studies with Buzz Away ®, however, indicated that the product can repel mosquitoes for about two hours.

Bite Blocker ®, a plant-based repellant that was released in 1997 containing soybean oil, geranium oil and coconut oil, has shown to be a good repellant for up to 3 1/2 hours against the Aedes mosquito (the mosquito that transmits Yellow Fever).

Citronella candles can be mildly effective mosquito repellants. One research study compared 3% citronella candles to plain candles in preventing bites from the Aedes mosquito. Persons near the citronella candles had 42% fewer bites than unprotected persons; ordinary candles provided a 23% reduction. In the same study, citronella incense was no more effective than plain candles in repelling mosquitoes.

Permethrin

Permethrin is a pesticide rather than a repellant. It is not for use on the skin, but is intended for clothing instead.

Permethrin products are sold in lawn, garden or sporting goods stores under names such as Permanone Repel ®. Unlike DEET, Permethrin can retain its potency for at least two weeks — even through several launderings. It can be applied to clothing, tent walls, and mosquito nets; Permethrin-sprayed mosquito nets have been used successfully in malaria prevention campaigns in Africa.

The combination of Permethrin-treated clothing and DEET-treated skin creates almost complete protection against mosquito bites. In field trials conducted in Alaska, Permethrin-treated clothing and 35% DEET on exposed skin provided greater than 99.9% protection.

Skin and bath products

Avon's Skin-So-Soft ® bath oil has gained popularity as a mosquito repellant, but its effects are only slight and not long-lasting. Skin-So-Soft ® is not nearly as effective as DEET.

In one study, the Avon product provided about half an hour of protection from mosquito bites (compared to greater than 10 hours from 35% DEET). Avon now markets some new products under the Skin-So-Soft ® label that contain an EPA-recognized chemical repellant.

Health Concerns Associated with DEET

Complaints of minor skin and eye irritation have been reported in the over 30 years that DEET has been in use. A few severe reactions have been reported, especially in children, either after swallowing or prolonged skin application. Reactions include headaches, nausea, disorientation, confusion and in some cases convulsions or death. However, if DEET products in moderate concentrations are used according to directions, they are considered safe. Following the EPA guidelines below will greatly reduce the possibility of toxicity.

Safe application of DEET

In all but the most unusual conditions high concentrations of DEET should not be used. Products with 10% to 35% DEET will provide adequate protection under most circumstances. The American Academy of Pediatrics recommends that repellants used on children contain no more than 30% DEET. While higher concentrations of DEET may be safe, the MSDH generally recommends using repellents with 10% or less on children. As with all repellants, DEET-based products should be applied only according to the directions on the product label.

DO

Use aerosol or pump sprays for treating skin and clothing. These products provide an even application.

Use liquids, creams, lotions or sticks to more precisely apply the product to exposed skin.

Wash DEET-covered skin with soap and water after outdoor activity.

Keep insect repellants out of the reach of children at all times.

DON'T

Apply to eyes, lips or mouth, or over cuts, wounds or irritated skin.

Over-apply to the skin, or saturate clothing.

Apply to skin beneath clothing, or to skin that is not exposed.

Apply more often than recommended on the product label.