Regulators in the European Union have moved to prohibit one ingredient commonly used in gel nail polish, trimethylbenzoyl diphenylphosphine oxide, known as TPO. The ingredient is a photoinitiator that helps gels cure under UV or LED light and harden into a durable, glossy finish. Reporting across outlets says the EU added TPO to its prohibited cosmetic substances in May 2025 and implemented a ban that took effect from September 1, 2025, as reported by several news outlets. National authorities urged distributors and salon owners to stop supplying or using products that contain TPO.
In the United Kingdom regulators set their own timetable, restricting the sale of new products containing TPO while allowing existing stock to be used in salons for a limited period. The Independent and ELLE reported that salons will be permitted to use existing TPO products until an off the shelf deadline on February 14, 2027, after which TPO-containing products should no longer be offered in commercial settings. The Health Products Regulatory Authority advised salons to review ingredient lists, dispose of TPO products responsibly and confirm future supplies are TPO free.
Reactions Risks And Alternatives For Salon Clients
European regulators based the prohibition on animal studies that linked high doses of TPO to reproductive harm, prompting the EU to classify the substance as hazardous under its hazard based framework, sources reported. Industry and scientific voices provided context. Caroline Rainsford of the Cosmetic, Toiletry and Perfumery Association said the doses used in the studies were far higher than exposure from nail polish and that application to the nail reduces absorption. ELLE quoted Dr Christine Hall saying regulators reclassified TPO as a Category 1B CMR substance with reproductive implications.
Experts in the United States told outlets the risk assessment differs there. Rosanne Paul, a dermatologist, said TPO remains considered acceptable in the US and that real world exposure during manicures is low. Chemists cited in reporting noted the EU follows a hazard based approach while US regulators use a risk based approach, taking exposure into account. Several stories cautioned that UV lamps used to cure gels pose separate concerns about skin ageing and DNA damage and referenced recommendations to use a broad spectrum sunscreen before exposure.
Manufacturers and salons are already shifting away from TPO. Cosmetic chemists and salon operators pointed to existing photoinitiator alternatives, including BAPO, Irgacure 819 and TPO L, and to product formats that avoid salon UV exposure. ELLE and feature reporting highlighted alternatives such as builder gels often called BIAB, dip powder systems that do not require curing lamps, and bio sourced gel polishes marketed as TPO free. Consumers were urged to ask salons about ingredients and product sourcing and to follow professional removal guidance from dermatology groups to protect nail health.
