A new wave of concern is sweeping through the beauty industry as the European Union has instituted a ban on trimethylbenzoyl diphenylphosphine oxide (TPO), a common chemical used in gel nail polish. Beginning on September 1, 2025, gel polishes containing TPO can no longer be sold or used in Europe. The ban, which has led many to question the safety of their favorite manicure, highlights a key difference in how Europe and the U.S. approach cosmetic regulation.
TPO is a photoinitiator, a chemical that plays a crucial role in gel manicures. When exposed to ultraviolet (UV) or LED light, it absorbs energy and triggers a chain reaction that hardens the polish into a solid film. According to cosmetic chemist Kelly Dobos, TPO is primarily used in gel nail polish and in other industries to cure inks and coatings.
The reason for the EU ban is its hazard-based approach to regulation. This means the EU regulates chemicals based on their inherent properties, rather than the real-world risks associated with how they are used. In this case, TPO was banned because animal studies, mostly in rats, found a risk of negative reproductive outcomes for males. However, as cosmetic chemist Doug Schoon notes, the high doses used in these studies bear no resemblance to the small amount of TPO placed on a human nail. No human studies on the reproductive toxicity of TPO have been conducted.
In contrast, the U.S. Food and Drug Administration (FDA) follows a risk-based regulatory approach. This considers both the potential hazard and the likelihood of exposure, allowing for a more nuanced decision that balances safety with functionality. Given this difference, Dobos believes it is unlikely the FDA will ban gel nail polishes with TPO at the federal level. However, she does suggest that some states might follow Europe's lead.
So, is gel nail polish with TPO safe to use? Based on current research, both Dobos and Schoon agree there is little to no reason to believe there are risks to fertility or overall health. This is because when TPO is applied to the nail, it is cured into a solid matrix, which "significantly limits systemic exposure."
For those who are still concerned, there are already TPO-free gel polishes on the market, and the selection is expected to grow as brands reformulate to comply with the European ban. Regular nail polish, which does not require UV light to cure, also does not contain TPO.
While the TPO ban is a new development, it is worth remembering that other health risks associated with gel manicures have been reported, primarily from UVA exposure. UVA rays penetrate the skin more deeply than UVB rays and are more likely to cause DNA mutations, which can increase the risk of skin cancer. However, this risk can be mitigated by using a broad-spectrum sunscreen on your hands or wearing UV-protective gloves during the manicure process.
