Product: Insect Shield Repellent Apparel — bandanna $8-$12, shirt $80 — available from L.L.Bean, Orvis and other outdoor brands. Info: www.insectshield.com.

Key ingredients: Permethrin, which is a man-made version of natural repellent found in chrysanthemum flowers.

The pitch: Effective against mosquitoes, ticks, ants, flies, chiggers and no-see-ums for up to 70 washings.

How it works: Permethrin is thought to stun or kill bugs by disrupting their nervous systems when they bite something coated with the chemical — or, perhaps, just get close to it.

Pros: The CDC advises travelers to insect-ridden regions to wear permethrin-containing repellents on clothing. In the 1990s, the National Academy of Sciences deemed combat uniforms pretreated with permethrin a safe and effective way to help the military prevent malaria and other insect-borne illnesses. A German study published earlier this year in the International Journal of Medical Microbiology found that permethrin-treated clothing provided a protection rate of 95.5 percent against certain ticks.

Cons: An Iranian study published earlier this year in the Eastern Mediterranean Health Journal found that DEET was more effective than permethrin in warding off mosquitoes on lab rabbits. A 1995 Bangkok study in the Journal of the American Mosquito Control Association found that permethrin-treated uniforms did not reduce malaria in Thai troops. An environmental publication called the Green Guide says the health and environmental effects of the clothing are still in question.

Bottom line: Those who spend a lot of time outdoors might want to invest in a shirt. A cheaper alternative is to buy a permethrin spray and treat your own clothing, although it won’t stay effective through as many washings.

— McClatchy Newspapers