New study finds endocrine disruptor enters the body via nail polish

nail polish stars
CC BY 3.0 Courtney Rhodes

Painting your nails could expose you to a potentially toxic chemical, triphenyl phosphate, suspected of being an endocrine disruptor.

A compound used as a plasticizer and furniture fire retardant, triphenyl phosphate (TPHP), which has been linked to hormone and reproductive irregularities, obesity, and other health issues, is also found in some nail polishes. And while painted nails may not seem like an easy pathway to exposure for potentially toxic chemicals (as opposed to ingesting or inhaling the substances), a recent study from researchers at Duke University and the Environmental Working Group (EWG) indicates otherwise, and suggests that TPHP directly enters the body during and after the polish is applied.

TPHP has been used as a replacement fire retardant compound in furniture, especially foams, following the phaseout of the previous generation of fire retardant compounds, the polybrominated diphenyl ether (PBDE) group. However, recent studies have found troubling links to increased health risks, especially hormone-related issues, with exposure to TPHP as well, and because it's an ingredient in a common beauty product, nail polish, and is not always disclosed on the label, painting your nails with certain brands of polish can carry a health risk with it.

The new study, Nailed, conducted by Dr. Johanna Congleton, a senior scientist at EWG, and Dr. Heather Stapleton, associate professor at Duke University, first tested 10 nail polishes for the existence of TPHP, none of which disclosed the chemical on their labels, and found it in 8 out of the 10. EWG has a listing of more than 3,000 nail polishes and treatments in its Skin Deep database, of which 49% list TPHP on their ingredients, but this recent finding of undisclosed TPHP in polishes suggests that it may be in more personal care products than was originally thought.

"The manufacturers likely added TPHP as a plasticizer, to render their polishes more flexible and durable. The concentrations in the eight nail polishes with TPHP ranged from 0.49 percent to 1.68 percent by weight. Clear polishes generally contained more TPHP than colored polishes." - EWG

For the second part of the study, authored by Drs. Emma Mendelssohn and Heather Stapleton, the team had 26 volunteers paint fake nails with the polish (not on themselves), using plastic gloves, and then tested their urine samples for the existence of a chemical called diphenyl phosphate (DPHP), which is what is created as the body metabolizes TPHP. When compared to urine samples taken before applying the polish, the levels of DPHP "did not change appreciably."

However, the next part of the experiment, with volunteers painting their own nails with the polish, found that within 10 to 14 hours of application, their urinary levels of DPHP had increased sevenfold, leading to the researchers' conclusion that "nail polish may be an important contributor to short-term TPHP exposure" and that for regular users of nail polish,"exposure to TPHP may be a long-term hazard."

"The conclusion is inescapable: any girl who paints her nails stands a chance of coming into contact with a potential hormone disruptor." - Heather White, EWG Executive Director

As a father of several daughters, one of whom is a teenager and is drawn to cosmetics regularly, and one of whom is just starting to be interested in things like nail polish, this connection is troubling to me.

While it's not exactly news to many of us that some of the chemical brews sold as beauty and bath products are potentially toxic to our health, it is cause for concern every time a link is found between an ingredient and higher health risks. And while there are a number of relatively 'clean' cosmetics on the market, many of them have a price tag higher than the rest of the options on the market (which frugal teenagers are not apt to choose), or are hard to find in retail outlets. That means that out of all of the bodycare chemical cocktails that are offered for sale, many times to kids, the hottest sellers are those with the lowest price and the best branding, not the least toxic ones.

Considering how relatively unfinished the human body is as a child, even as an older teenager, it seems to be a dangerous game we're playing with the futures of our children through the widespread use of ingredients linked to symptoms such as early onset puberty, obesity, unbalanced sex hormone production, low sperm count, etc.. However, the good news is that with diligent research and attention to details, we can minimize our kids' (and our own) exposure to potentially hazardous chemicals in our personal care items, and thanks to the work of organizations such as EWG, with its expansive work toward protecting human health and the environment.

Tags: Beauty Treatments | Health


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