Permethrin is a pesticide in a class known as pyrethroids, and research suggests that it poses some potential health risks.
A 2019 study that followed more than 2,000 adults over the age of 14 found that those most exposed to pyrethroids had an increased risk of dying from heart disease. (The study involved a small number of people, however, and could not establish whether pyrethroids caused the deaths or if another factor was to blame.)
Like many other pesticides, permethrin has also been implicated as a possible endocrine disruptor, notes CR lead scientist Michael Hansen, PhD. Endocrine disruptors mimic or block the activity of your hormones, which can have effects throughout your body and brain.
Research suggests that permethrin can be found in the blood and urine of workers wearing treated clothing, meaning it can be absorbed through clothing into the body. In a 2019 study, permethrin levels found in workers’ urine were well below Environmental Protection Agency and World Health Organization limits for safe exposure to the chemical.
But endocrine disruptors have the potential to cause harm at doses well below legal limits, Hansen warns. Young children and pregnant women may be most exposed to endocrine disruptors, so for people in these groups it is wise to think carefully about minimizing exposure (for example, using clothing treated infrequently or only in most risky situations).
Ultimately, you’ll need to weigh the possible health risks of permethrin against the risk of contracting a tick-borne disease, many of which can have serious and lasting health consequences.
If you choose to treat your garments yourself, additional safety measures are necessary. First, be sure to use a spray formulated specifically for clothing; do not buy or use agricultural grade permethrin, even if you dilute it.
Second, never spray while wearing the clothes you want to treat; clothes should be spray-dried and then dried completely before wearing. Permethrin should also never be sprayed around cats, to whom it is highly toxic. (See these tips on safe use of permethrin.)
Permethrin isn’t your only option for protection. According to public health experts, simple adjustments can make a big difference, such as wearing light-colored pants and long sleeves when you’re in tick habitat, tucking in your shirt, pulling your socks up over your pants, and , when you come back. at home – check for ticks and shower.
You can also consider insect repellents containing deet, picaridin, and oil of lemon eucalyptus, all of which are EPA-registered for protection against ticks.