The European Union is now prohibiting the use of a key chemical ingredient in some gel nail polishes and other cosmetic products.
The ban, which went into effect this week, targets the use of trimethylbenzoyl diphenylphosphine oxide or TPO, which was classified as a type of “reproductive toxicant” by European regulators, according to the European Commission.
TPO works as a photoinitiator, meaning it responds to light. In gel nail polish, it helps the polish set under ultraviolet or UV light.
“It starts that reaction that gets it to cure,” said Kelly Dobos, a cosmetic chemist and adjunct instructor at the University of Cincinnati’s James L. Winkle College of Pharmacy, who has been following the European regulation.
Some people may prefer gel nail polishes over regular nail polishes because gel products generally last longer, are harder in texture and dry more quickly after a manicure or pedicure.
TPO-containing products are primarily used in salons because the chemical requires a nail lamp with UV light to cure or harden the gel, said David Andrews, acting chief science officer at the nonprofit Environmental Working Group, a nonprofit consumer advocacy group that maintains a database on personal care products that contain potentialtoxins.
“Exposure to TPO is of greater concern for salon workers and consumers who frequently get professional gel nail polish,” Andrews said in an email.
“The EU has banned the use of TPO both at home and professionally due to reproductive toxicity concerns identified in animal studies,” he added. “The toxicity studies completed on animals showed testicular abnormalities and reduced fertility.”
Although TPO has been associated with some concerns in animal studies, people who have enjoyed receiving gel manicures should not panic, Dobos said.
“What’s important to keep in mind is that those end points and those studies were from animal-feeding studies,” she said. “When you’re thinking about nail polish, that’s clearly not how we’re exposed to TPO. You’re not eating the nail polish. So, it’s a different route of exposure.”
When applied to the fingernails of humans, “in my opinion, these materials, inthe way that they are used, are very safe, but there are alternatives,” she said.
“Some brands have started to think about reformulation, and some brands had already used alternate photoinitiators. So there are options without TPO. When you go to a salon, though, you don’t always get to see the label of the products you’re using. So you’re going to have to ask at the salon,” Dobos said. “Or you can also just get a good old-fashioned nail polish. Old-fashioned nail polish has been around since the 1920s and has a long history of safe use. I still go for the old-fashioned nail polish myself.”
The new restrictions in Europe do not mean gel polish itself is prohibited. The prohibition applies only to those products containing TPO, according to the Nail Manufacturer Council on Safety, part of the Professional Beauty Association, a nonprofit advocacy community for beauty professionals across the United States.
“Some headlines have caused unnecessary worry by calling this a ‘ban on gel polish,’ but that’s simply not true, consumers and professionals can be reassured: gel polish products remain fully available and legally marketable in the EU, provided they are formulated with approved alternatives,” Doug Schoon, chair of the Nail Manufacturer Council on Safety, said in a statement. “This is a regulatory restriction on a single ingredient, not a ban on an entire product category.”
Under the European ban, TPO-containing products should no longer be sold, supplied or used, according to the European Commission. Any TPO-containing products still in stock should be withdrawn from the market, and new products containing TPO cannot be placed on the market.
However, “I wouldn’t be surprised if we see state-level activity. There have been a lot of state-level ingredient bans in recent years,” Dobos said. For instance, in 2023, California banned 26 chemicals used in many cosmetics, including hair products, bodywash and nail polish.
More manufacturers may start to remove TPO from their products, Andrews said, but he said “it’s unlikely” the FDA will ban the chemical in the United States.
“The EU takes a proactive approach of restricting and banning chemicals that are identified as causing health harms, mostly in animals, while the US FDA approach is more just wait and see if anything bad happens,” he said.
