UNITED KINGDOM – The United Kingdom has begun phasing out gel nail products containing Trimethylbenzoyl Diphenylphosphine Oxide (TPO), a chemical widely used to help gel nail products harden under UV and LED lamps.
The new restrictions came into force on August 15, 2026, adding TPO to the list of substances prohibited in cosmetic products under the UK’s cosmetics regulations. The rules apply to Great Britain — England, Scotland and Wales. Northern Ireland operates under a separate cosmetics framework.
The change does not ban gel manicures themselves. Instead, it prevents manufacturers and importers from placing new cosmetic products containing TPO on the Great Britain market.
The industry now has a transition period to clear existing products and move towards TPO-free formulations.
TPO, whose full ingredient name is Trimethylbenzoyl Diphenylphosphine Oxide, is a photoinitiator used in UV- and LED-cured nail products.
When exposed to the light from a curing lamp, the chemical helps the gel polymerise and harden. This allows gel polish and other professional nail systems to achieve the durable finish that makes them popular with consumers.
The ingredient has been used in a range of gel nail products, including some gel polishes and builder-gel systems. Customers can identify it on an ingredient list by its full name rather than simply the abbreviation “TPO”.
The restriction follows the classification of TPO as a carcinogenic, mutagenic or toxic-for-reproduction (CMR) substance under chemicals legislation.
The UK’s 2026 regulations added a number of CMR substances to the list of ingredients prohibited in cosmetics. TPO was among the substances included, with the prohibition applying from August 15, 2026.
The decision follows similar action by the European Union, where TPO was prohibited in cosmetics from September 1, 2025, following its classification as potentially harmful to reproduction.
The Cosmetic, Toiletry and Perfumery Association (CTPA) has stressed that the classification does not mean ordinary use of TPO-containing nail products has been shown to cause infertility in salon customers.
CTPA Director of Science Caroline Rainsford said the prohibition is based on the ingredient’s hazardous properties under a “worst-case” exposure scenario.
She said the quantity used in nail products is more than 1,000 times lower than the amount associated with negative effects on fertility in the relevant assessment, while the products are applied to the nails, limiting potential exposure.
The UK has introduced the restriction in stages.
From August 15, manufacturers and importers can no longer place new TPO-containing cosmetic products on the Great Britain market. This is known as the “placing on the market” deadline.
The next major deadline is February 14, 2027, when the remaining TPO-containing products reach the “making available” or off-shelf deadline.
The CTPA says professional nail technicians may continue using products they already have after that date under its interpretation of the rules, but they cannot purchase those products from distributors once the deadline passes. CTPA said it had discussed this interpretation with UK Trading Standards.
This means the rules do not require salons to immediately throw away every TPO-containing product they purchased before August 15.
The transition means consumers are unlikely to see the end of gel manicures. Instead, they are likely to see more products labelled or marketed as TPO-free.
Anyone concerned about TPO can check the ingredient list of their gel nail products. The name to look for is: Trimethylbenzoyl Diphenylphosphine Oxide
UK cosmetic products must provide ingredient information on their packaging, while products placed on the Great Britain market must comply with safety and notification requirements.
Consumers should also be cautious when purchasing gel products from unfamiliar online sellers. The UK’s Office for Product Safety and Standards advises consumers to pay attention to missing product information, unclear sellers and products without an identifiable Responsible Person.
The UK is not the first major market to restrict TPO.
The European Union prohibited TPO in cosmetics from September 1, 2025, after the ingredient was classified under its chemicals framework. European regulators and market surveillance authorities have since taken action against nail products containing prohibited TPO.
The change in the UK and EU is also likely to influence international beauty-product supply chains as manufacturers increasingly develop formulations that can be sold across multiple markets.
