The EWG Warns Against Using Natural Bug Spray This Summer. Here's Why

In a new analysis, EWG scientists have ranked repellents in order of effectiveness:

In laboratory conditions, these repellents offer strong protection from the Aedes mosquito for at least four hours. It's important to reapply after swimming and sweating.

Some essential oils may work for short periods of time, but others are ineffective against Aedes mosquitoes. Due to the serious risks posed by Zika, EWG does not recommend blends of essential oils for people at risk of mosquito-borne infection.

Look out for synthetic repellents approved by the U.S. Environmental Protection Agency1, and follow label instructions closely. Make sure to use these repellents as directed, but don't over-apply. Here are the details about a few we recommend using:

Always handle DEET with caution. It irritates the eyes and in intense doses may induce neurological damage. In very rare cases it has been reported to impair the nervous system, with symptoms including seizures, tremors, and slurred speech, most often after exposure to high concentrations. Infants and children may be more sensitive to these rare neurological side effects.

The EPA says that picaridin has not induced developmental problems in the offspring of animals exposed to it; it harmed young animals only when their mothers had been exposed to doses so high they were toxic.

In animal tests, IR3535 harmed young animals only when the mothers were exposed to toxic levels of the chemical. IR3535 has not been tested for effects on human pregnancies.

Oil of lemon eucalyptus and PMD have not been thoroughly tested for their effects on children under 3 years old. The EWG advises against using them on pregnant and nursing women, babies, and toddlers. They are also less effective than other chemicals against Aedes mosquitoes that transmit the Zika virus.

When infused into clothing, permethrin can deter mosquitoes from landing and prevent bites. However, CDC officials said that recent tests in Puerto Rico indicated that permethrin "probably isn't effective" in the current pandemic, so they dropped a plan to distribute permethrin-treated clothing. The chemical's effectiveness declines after washing. If you want to try it, buy clothing pre-treated at the factory. Don't treat your own clothing with liquid permethrin.

Clothing is the first choice for both sun and mosquito protection. Make sure that the material is sturdy to prevent bites. If you need both sun and mosquito protection, the CDC recommends buying two separate products and applying sunscreen first and then mosquito repellent. Studies show that ingredients in sunscreen increase your skin's capacity to absorb repellent.