Repellents, clothing, netting and other personal protection measures can help prevent mosquito bites and the diseases they carry.
Insect repellents are effective and safe when properly used. Use the information below to select the repellent that best fits your exposure to mosquitoes.
DEET (N,N-diethyl-3-methylbenzamide) is a reliable and highly effective insect repellent. The chemical has been in public use since 1957.
The repellent is sold under numerous brand names 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. However, products with concentrations higher than about 50% do not offer significantly 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. The safe application of DEET is explained further below.
Picaridin, also known as KBR 3023, is an effective alternative to DEET products which provides long-lasting protection against mosquito bites. This repellent has been used worldwide since 1998. Compared to DEET, Picaridin is nearly odorless, does not cause skin irritation, and has no adverse effect on plastics.
Products with DEET and picaridin can be expected to provide better and longer-lasting protection than plant-based repellents.
Permethrin is effective both as a pesticide and as a repellent. It is not for use on the skin, but is intended for clothing.
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. The combination of Permethrin-treated clothing and DEET products applied to skin can offer excellent protection against mosquito bites even in demanding conditions.
Other Recommended Products
Oil of lemon eucalyptus
Oil of lemon eucalyptus is found naturally in eucalyptus leaves and twigs. PMD (p-Mentane-3,8-diol) is the synthetic form of the chemical. Oil of lemon eucalyptus has been tested against mosquitoes found in the US, and provides protection similar to repellents with low concentrations of DEET. Oil of lemon eucalyptus products should not be used on children under the age of three.
IR-3535 is used as an insect repellent against mosquitoes, deer ticks, and biting flies. It can be expected to provide reasonably long-lasting protection for those seeking a non-DEET product.
Repellents derived from plants such as citronella, geranium, basil, garlic and peppermint generally provide much more limited protection against mosquitoes. Studies with products containing a mixture of plant oils (citronella, cajuput, lavender, safrole-free sassafras, peppermint, calendula, soy and tea tree oils) have shown a limited effect in the best of circumstances, repelling mosquitoes for about two hours.
Oil of citronella products are commonly sold as repellent candles, but these have little effectiveness against mosquitoes. Skin-applied products containing oil of citronella can offer mild protection against mosquitoes.
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. 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 repellents 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 repellents, DEET-based products should be applied only according to the directions on the product label.
- 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 repellents out of the reach of children at all times.
- 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.
For more discussion of mosquito repellent recommendations, see the CDC site below.