Potentially Harmful Nail Polish Ingredient Found in Women’s Bodies

A joint study from researchers at Duke University and the Environmental Working Group (EWG) found that a suspected endocrine-disrupting chemical in many popular nail polishes was also found in the bodies of women who had painted their nails with polishes containing the substance.

Even though the study was small — conducted on 26 women — the researchers discovered that two to six hours after they painted their nails, 24 of the 26 volunteers in the study had slightly elevated levels of a form of triphenyl phosphate called diphenyl phosphate (DPHP) in their urine. But ten to 14 hours after polishing their nails, the DPHP levels in all 26 participants had risen by an average of nearly sevenfold, suggesting that more of the TPHP had entered their bodies and been metabolized into DPHP.

TPHP is a known plasticizer (i.e. it makes products more flexible and less brittle) and is also used as a fire retardant in furniture.

Scientists studied more than 3,000 nail products in EWG’s Skin Deep database and discovered TPHP listed on the label of nail polishes from the following brands:

    Sally Hansen
    Essie
    OPI
    Butter LONDON
    Revlon
    Milani
    Wet N Wild
    SpaRitual
    Orly
    theBalm
    Nuance by Salma Hayek
    Maybelline
    Beauty Without Cruelty


While everyone has some level of TPHP in their body, study co-author Kate Hoffman, PhD, a researcher at Duke University, tells Yahoo Health that the levels found in women who painted their nails were “substantially higher” than what is typically found in the general population.

Johanna Congleton, PhD, MSPH, a senior scientist with EWG, who also worked on the study, tells Yahoo Health, that nail polish can be a “significant source” of short-term TPHP exposure, as well as a source of chronic exposure for people who use it frequently.



Researchers conducted two sets of experiments to find out whether the TPHP was inhaled or absorbed and found levels of DPHP did not increase significantly when women didn’t apply the polish directly to their own nails.

“Nails aren’t permeable to most molecules, but TPHP could be absorbed into the cuticle or around the nail,” says Congleton.

But what does this mean for your health? Experts aren’t sure.

Here’s what they do know: Several lab studies have found that exposure to TPHP caused endocrine disruption and, in animal studies, TPHP exposure caused reproductive and developmental issues.

According to the National Institute of Environmental Health Sciences (NIH), endocrine disruptors are chemicals that may interfere with the body’s endocrine system. Previous research has found endocrine disruptors to play a role in infertility, hormone-related cancers (such as breast and ovarian cancer), prostate conditions, thyroid disorders, neurological issues, diabetes and even obesity.

“We don’t have a lot of human data, but the scarce data that we do have indicates that it might disrupt the endocrine system,” Congleton says.



Many brands will list TPHP as an ingredient on their packaging, but Hoffman notes that they tested several brands that contained TPHP but didn’t list it as an ingredient.

“TPHP could be difficult to avoid in nail polish,” she says. “We think our findings may underestimate the number of nail polishes that it’s in.”

So, should you stop painting your nails altogether?

Hoffman is hesitant to go that far, but urges consumers to be cautious.

“People get really upset about phthalates in plastics but they don’t think about what’s in the cosmetics they’re applying directly to their skin,” she says. “The skin is an organ that takes it all in.”

If you plan on painting your nails, she recommends avoiding brands that list TPHP as an ingredient (just be aware that it doesn’t mean your polish is definitely TPHP-free). She also advises avoiding the cuticle and surrounding skin as much as possible to try to minimize absorption.

But Congleton says the findings underscore the need for better regulation of cosmetics. “We shouldn’t be in this situation,” she says. “We need to make sure we have a clear picture of the safety data before these compounds wind up in products and people’s bodies.”