Take a close look at your fingernails—if you’re like many women, you’re probably wearing nail polish.

In today’s world, polish is often seen as part of good grooming and personal style. But beneath the glossy finish, this beauty staple may carry hidden health hazards.

Toxic Chemicals Absorbed Through the Skin

A study by Duke University and the Environmental Working Group (EWG), published in Environment International, revealed that nail polish chemicals can enter the body quickly—within two hours of application.

Researchers monitored 24 women and found a sharp increase in diphenyl phosphate (DPHP) levels in their urine just 10 to 14 hours after applying polish. DPHP forms in the body when it metabolizes triphenyl phosphate (TPHP), a chemical commonly used in nail polish as a plasticizer to make it more flexible and chip-resistant.

What’s concerning is that TPHP has been linked to serious health issues, including infertility, hormone-related cancers (like breast and ovarian cancer), thyroid problems, neurological disorders, obesity, and diabetes.

“Nails aren’t usually permeable, but TPHP can be absorbed through the cuticles or surrounding skin,” explains EWG senior scientist Johanna Congleton, a co-author of the study. It can also enter the body through inhalation during application or by nail biting.

“It’s troubling that a suspected endocrine disruptor is being marketed to women and young girls,” says Congleton. “Even more troubling is how quickly it’s absorbed after use.”

What the Study Found—and What It Didn’t Say on the Label

In a follow-up test, researchers analyzed 10 popular nail polishes and found TPHP in 8 of them. Two didn’t disclose the chemical on their labels. These brands are commonly sold across North American drugstores and beauty shops.