Why Have Some Gel Nail Polishes Just Been Banned In Europe?

Now, we admit that sounds bad – so what’s really going on? The ban concerns trimethylbenzoyl diphenylphosphine oxide, more commonly known as TPO for obvious syllable-related reasons – a chemical photoinitiator that gives gel polishes their quick curing time under ultraviolet light. It’s been used like this for decades, and not only in nail polishes – but it’s also long been scrutinized for potentially harmful effects on fertility, leading the European Commission to now label the substance as “carcinogenic, mutagenic, or reprotoxic” (CMR).

Perhaps surprisingly, that alone wouldn’t necessarily sound the death knell for TPO in gel polishes. “An industry can voluntarily defend continued use of cosmetic ingredients that receive a harmonized classification as a CMR,” Francesca Rapolla, scientific affairs manager at The Cosmetic, Toiletry & Perfumery Association, told industry magazine Scratch this week. All it would take, she explained, would be “submitting thorough safety dossiers that meet the specific exemption criteria of Article 15 of the EU Cosmetics Regulation.”

But “in the case of TPO, the industry did not, and could not, defend the continued use of this ingredient in nail products,” Rapolla continued, “mainly because it could not demonstrate that there are no alternative ingredients to this one. Therefore, TPO is prohibited for use in cosmetics used within the EU.”

Before you freak out about the contents of your nail polish stash, though, there’s a few things to understand here. The EU and US famously have very different approaches to regulation, with the former union often trending more cautious than the latter. In that respect, this new ban is pretty par for the course: “Removing TPO from nail coatings is not in response to problems with nail products containing this ingredient, but rather as precautionary approach to consumer safety,” Doug Schoon, a scientific expert in the nail industry and founder of Schoon Scientific, told Scratch.

But the evidence supporting the ban is, admittedly, light. Better safe than sorry, the EU may argue, but if you’re in the US and worried about being exposed to TPO, perhaps it’ll reassure you that the three main studies cited in the European Chemical Agency’s 2021 risk assessment were all undertaken in rats, with relatively huge doses of the chemical administered orally – and as you may be aware, that’s not usually how gel nail polish is used.

On top of that, industry professionals argue that, once cured, the TPO is essentially harmless. “[It] is completely used up: it does not remain intact and no longer exists in its original form,” says Belgian nail care company ProNails. 

“After curing, TPO can be incorporated into the cured structure or converted into harmless by-products,” the company explains. “In either case, it remains locked up in the cured gel: it cannot evaporate, move or come into contact with the skin – it is like being sealed in a vault. Even if a tiny residue were not used up, it is mainly in the adhesive layer, where the unreacted molecules are, and in an amount of less than 0.1 percent.”

In other words: unless you’re feeling incredibly cautious, there’s probably no burning reason to throw out your unfinished gel polishes. But what about all those newly drab-nailed Europeans?

Well, fear not. “The removal of TPO from nail products doesn’t necessarily impact their performance,” Schoon said, and indeed not all gel polishes even include the chemical. 

“Brands can support [the] transition by reformulating products with safer photo initiators, providing education on proper application techniques for new formulas, and by clearly labelling TPO-free options,” Schoon explained.