Many men and women are so tied up in the pursuit of beauty that they neglect important questions — like if the products they’re using contain hazardous chemicals. A recent study conducted by researchers from Duke University and the Environmental Working Group has found a toxic chemical, triphenyl phosphate (TPHP), in nail polish commonly used to manufacture plastic and a fire retardant in foam furniture.

“It is very troubling that nail polish being marketed to women and teenage girls contains a suspected endocrine disruptor,” said Dr. Johanna Congleton, a senior scientist at EWG and co-author of the Duke-EWG study, in a statement. “It is even more troubling to learn that their bodies absorb this chemical relatively quickly after they apply a coat of polish.”

Congleton and her colleagues conducted two different experiments. First, they tested 10 nail polish samples for TPHP, a chemical that manufacturers add to make their polishes more flexible and durable. TPHP was found in eight of the 10 samples and was not listed on the ingredient lists for two of the samples.

In the second experiment, the research team tested urine samples from 26 female volunteers. Twenty-four volunteers experienced slightly elevated levels of diphenyl phosphate (DPHP) — a chemical created when the body metabolizes TPHP — two to six hours after painting their nails. DPHP levels in all 26 participants had increased sevenfold 10 to 14 hours after polishing their nails.

“It is possible that TPHP is now being used in nail polish as a replacement for phthalates, which also have endocrine-disrupting properties and are toxic to the reproductive system,” said Dr. Heather Stapleton, associate professor at Duke University and principal investigator of the Duke-EWG study. “However, it’s not clear that TPHP is the better alternative. There is growing evidence suggesting that TPHP may affect hormone regulation, metabolism, reproduction, and development.”

Nail polish companies started using TPHP as a replacement for dibutyl phthalate (DBP) after studies showed that they lead to endocrine disruption and can be toxic to the reproductive system. Similar studies have shown that exposure to TPHP can also disrupt endocrine function and animal studies have found reproductive and developmental complications. A newer study has even tied the chemical to obesity.

“It is alarming to think my ruby red nail polish could come with a side of toxic ingredients that could ultimately end up in my body,” said entrepreneur and eco expert Erin Schrode. “We cannot control far too many exposures to harmful chemicals in our world today, but each of us can become informed and spread the word, support legislation that protects our health, and make smarter choices whenever possible. By voting with our dollars we can shift the marketplace toward safer, healthier products… beginning with my own bottle of bright, glossy nail polish.”

While researchers from this new study decided to focus on nail polish, a similar study conducted by researchers from the University of Missouri and SUNY Albany suggests there are similar chemicals hiding in other personal-care products people use every day. They found that endocrine-disrupting chemicals responsible for early menopause were present in products commonly used by women, including perfumes, makeup, lotions, hair spray, and even liquid soap.

Source: Mendelsohn E, Stapleton H, Congleton J, et al. Nail polish as a source of exposure to triphenyl phosphate. Environmental International. 2015.