Manufacturers of special permethrin-treated clothing promise it will protect you from mosquitoes. Permethrin is a chemical insecticide approved by the Environmental Protection Agency against a wide range of insects, everything from ticks to mosquitoes.
L.L.Bean and ExOfficio say their shirts will repel mosquitoes and other bugs for up to 70 washings. The shirts don’t come cheap, costing more than $70.
Consumer Reports tested to see how well the shirts prevent mosquito bites, both when new and after being washed 25 times. Volunteers put their arms into cages with 200 mosquitoes. The permethrin-treated clothing did stun or kill many mosquitoes that landed, but none was foolproof in preventing mosquito bites.
The volunteers were not bitten when wearing the new L.L.Bean shirt, but after the shirt had been washed, Aedes mosquitoes that can carry the Zika virus bit three out of four testers. With the ExOfficio shirts, both new and washed, all four testers received bites from the Aedes mosquitoes as well as Culex mosquitoes, which can carry the West Nile virus.
Consumer Reports contacted the companies that make the permethrin treatment, Burlington and Insect Shield. Both cited formal studies and field-testing data to underscore the effectiveness of their products. And a government expert says the clothing can reduce the number of mosquitoes right around you.
There is another way protect yourself, according to the Centers for Disease Control and Prevention. Any repellent that works on your skin should work for just as long when applied to clothing.
Consumer Reports tried the same test with a regular shirt sprayed with a 30 percent deet insect repellent. None of the volunteers were bitten. If you do try this, Consumer Reports advises spraying your clothes before you put them on and waiting until they’re completely dry.