Key Takeaways:
On September 1, 2025, the European Union banned trimethylbenzoyl diphenylphosphine oxide (TPO) from all nail products. For salons, this meant pulling best-selling gels from shelves and treatment menus overnight. For brands, it meant reformulating core SKUs at speed. But beyond the immediate disruption, the ban is exposing a deeper divide between European and US beauty regulation, sparking questions about who should set the standard for safety.
TPO is a photoinitiator, the ingredient that makes gel polish harden quickly and evenly under LED or UV lamps. It’s prized for maintaining bright white shades, cutting curing time, and ensuring a long-lasting finish. In 2024, the EU’s independent Scientific Committee on Consumer Safety (SCCS) reviewed TPO and found it safe for professional use up to 5%, assuming correct application and curing. At the time, regulators considered exposure risks minimal.
Since then, the European Union officially banned TPO in all nail products, classifying it as a Category 1B CMR substance, suspected of being carcinogenic, mutagenic, or toxic to reproduction. Under EU law, once an ingredient receives this classification, it cannot be used in cosmetics unless an exemption is granted. In TPO’s case, no exemption was requested, largely because safer alternatives already exist.
Animal studies suggest TPO may interfere with fertility and long-term health, though direct human data are limited. Still, with substitutes readily available, regulators chose a total phaseout rather than risk consumer exposure. This process reflects the EU’s hazard-based approach: Ingredients are restricted based on what they could do under worst-case conditions, not necessarily how they’re used in practice.
The Industry Responds
For Europe’s nail industry, the impact was swift. Salons had to pull TPO-based products from backbars with no grace period, leaving many scrambling for compliant alternatives mid-booking. Manufacturers fast-tracked reformulations and distributors swapped out retail stock. Consumers also saw disruption, as favorite gels disappeared and were replaced by new “TPO-free” systems marketed as safer and more future-proof. Though disruptive, the shift has accelerated the adoption of next-generation curing agents and positioned Europe as the benchmark for cleaner nail innovation.
So why would manufacturers use TPO in the first place if there are viable alternatives? We asked Mohammed Kanadil, a toxicologist and cosmetics safety assessor, who explained in an email to BeautyMatter that TPO delivers superior performance compared to other photoinitiators (molecules that create reactive species like free radicals when exposed to UV or visible radiation). TPO is highly efficient under the UV lights used by most professional salon lamps, enabling fast curing, strong conversion, and a durable, high-gloss finish. Another advantage to using TPO, according to Kanadil, is that it avoids the use of tertiary amines, which can cause yellowing and color instability. “TPO offers formulators both versatility and reliability in achieving premium nail gel performance,” Kanadil said.
In an open letter, chemist and nail industry scientist Doug Schoon criticized the EU’s hazard-only framework. “These findings arise exclusively from oral toxicity studies in laboratory animals,” Schoon wrote in the letter. “The exposure conditions in these animal studies bear no resemblance to realistic exposure scenarios in cosmetic use.” He warned the ruling will impose unnecessary economic burdens on small businesses, waste safe products, and undermine trust in regulatory proportionality. Schoon draws a parallel to the 1980s ban on benzoyl peroxide, which was later partially reversed when regulators acknowledged the original measure was overly broad.
While critics like Schoon argue the ban ignores real-world exposure, toxicologists point out the science around TPO hasn’t suddenly changed. As Kanadil explained to BeautyMatter in an email, “[The change in regulation is] not a new finding that cured nail gels are now intrinsically unsafe.” Kanadil went on to explain that the 2014 SCCS opinion already built in extremely conservative assumptions, assuming 1% of TPO remained in cured gels, and that the body absorbed 100% of that residue, even though nails are an effective barrier and photoinitiators are largely locked inside hardened polymers. Even under the worst conditions, the margin of safety came out to around 1,500, far above the regulatory threshold of 100.
Kanadil emphasized that the risk assessment has not changed, but the regulatory process has. “The instant TPO was assigned a CLP CMR 1B classification, Article 15 of the Cosmetics Regulation called for prohibition unless a new derogation dossier was provided and positively reassessed by SCCS. If the industry wanted to continue with TPO, new data should have been filed under Article 15(2).”
Regulatory expert Kam Kaur, founder of The Cosmetic Regulator, emphasized in an email that the TPO ban was triggered by worst-case use scenarios, which do not reflect the low percent TPO is used in cosmetic products as EU law takes a very strict approach. “The EU will always take an overly cautious approach as consumer safety is paramount. TPO was banned, not via the Cosmetics Regulation, but by the EU CLP regulation … This almost provides an additional ‘layer’ of consumer protection.”
Why wasn’t a derogation filed? Kaur explained that the bar was high. “Substances such as TPO, which are classified under CLP as a CMR 1B, must satisfy four conditions before they can be used in cosmetics … Providing the additional information to satisfy all four points was proving difficult for industry, especially when we are thinking about safe for use in food, and therefore no derogation was sought by the industry even though the safety of TPO could be proved.”
The case highlights how regulatory design can create disruption. “This process shows the EU takes a very strict approach when it comes to banning ingredients in cosmetic products … Even though the ban on TPO is based on a worst-case scenario, the EU will use this worst-case data to amend regulations,” said Kaur.
In an email to BeautyMatter, Schoon explained that he believed there are many things to consider when determining the safety of an ingredient. “The concentration of use, how much exposure occurs and how often, and routes of exposure that cause toxicity, are just a few of the basic considerations when determining safety.”
What It Means for the US
TPO remains legal and widely used in US gels. The FDA does not operate under the EU’s precautionary principle, meaning ingredients typically remain available until strong human health data compels removal. As a result, US salons and retailers continue to use TPO products, with most consumers unaware of its banned status not only in the EU but also in Morocco. This has created a two-tier global market: Brands must develop TPO-free lines for Europe, while selling TPO-inclusive products in the US, raising questions on transparency, consistency, and the American beauty standards. Although Great Britain neighbors the EU, the ban does not affect the British market yet; the ban is expected to be implemented at the end of 2026.
For American indie beauty brands, the EU ban isn’t just a regulatory issue; it’s a business decision. Meredith Petillo, Vice President of Technical & Regulatory Affairs at the Independent Beauty Association (IBA), explained to BeautyMatter in an email that international regulatory requirements often factor into US indie beauty brand formulation strategies. However, “economies of scale make it difficult for independent brands to maintain country or region-specific formulas for the same product, especially for a category like nail, where the number of SKUs quickly proliferates due to seasonal launches and trend-driven shades and finishes."
For these brands, the choice often comes down to reformulating globally versus limiting market access. Petillo explained that today, many indie brands are looking at exporting their cosmetic products much earlier in their brand growth compared to 15-20 years ago.
“Therefore, some US based brands that currently only distribute domestically are likely evaluating between two pathways: either reformulate to proactively prepare for export to the EU if they want to maintain one global formula, or keep their US formulas as-is and make a business decision to not offer impacted products to the EU and countries that closely follow EU cosmetic regulations in the future.” This global effect highlights how single EU decisions can reshape business strategy far beyond Europe’s borders; not just in terms of safety, but also cost, portfolio planning, and consumer trust.
The EU’s TPO ban could ripple into the US market, even without FDA action. Advocacy groups may push for tighter oversight, while retailers like Ulta Beauty, Target, and Amazon could voluntarily pivot to TPO-free assortments. For indie beauty brands, this moment offers a chance to market safer, future-forward formulas, but with most US shoppers unaware of what "TPO" means, brands must balance education and transparency to avoid consumer backlash.
The debate over TPO underscores a larger divide in how global markets approach beauty regulation. Europe, and now countries like Morocco, are leaning into the precautionary principle, banning ingredients once classified as potentially hazardous regardless of real-world risk. The US, by contrast, typically waits for conclusive human data before taking regulatory action, leaving ingredients like TPO legally on shelves. This divergence creates complex challenges for brands, particularly indie players with fewer resources, who must choose between reformulating globally or limiting access to international markets. At the same time, it offers opportunities: retailers that act and brands that lead with transparency and education stand to build stronger trust with consumers. Ultimately, TPO is more than a nail ingredient; it’s a flashpoint in the ongoing evolution of beauty standards, scientific interpretation, and consumer expectations worldwide.
The EU’s ban on TPO shows how quickly regulation can reshape entire product categories, not because of science, but because of how laws interpret and act on potential hazards. While Europe leans on the precautionary principle, the US remains anchored in risk-based regulation, creating a split market where the same product can be banned in Paris but sold in New York. For brands, this is no longer about one photoinitiator; it’s about navigating a regulatory landscape where scientific nuance, legal frameworks, and consumer trust collide.
