The European Union has banned an ingredient commonly used in gel-polish after deeming it potentially toxic to humans.
Trimethylbenzoyl diphenylphosphine oxide (TPO) has been forbidden for use in cosmetic products as of 1 September 2025 after being classified as a CMR 1B substance – a category for chemicals considered potentially harmful to fertility.
From that date, gel-polish products and other cosmetics containing the affected ingredient must no longer be used, sold or made available on the market.
TPO is known as a ‘photoinitiator’ – used in several gel-polish and hybrid nail polishes as it helps products to harden and cure under UV light quickly.
It has been banned by the EU’s 27 member states, as well as by countries which mirror the trade bloc's regulations, such as Norway and Switzerland.
The ban comes after some studies have potentially highlighted a link between the chemical and long-term fertility damage in animals.
TPO was added to the EU Commission’s legislation – the 7th CMR Omnibus Regulation – which contains a list of ingredients prohibited for use in cosmetics.
The Classification, Labelling and Packaging (CLP) Regulations in the EU aims to ensure a high level of protection of human health and the environment by identifying hazardous properties of substances and mixtures.
Under the EU CLP Regulation (Regulation (EC) No 1272/2008), substances deemed carcinogenic, mutagenic or reprotoxic (CMR) are classified into three categories based on the strength of evidence for their hazardous effects.
Under the CLP, TPO is now classified as belonging to the CMR Category 1B, resulting in its inclusion in Annex II of the European Cosmetics Regulation and prohibiting its use in cosmetic products.
Category CMR1B is for substances “for which these effects are possible but for which there is a need for further research for confirmation of the effects”.
The UK is on a separate timeline, with its own ban not expected until late 2026, while the US has not yet regulated TPO.
Distributors in the EU should not supply any products containing TPO after 1 September.
Salon owners need to check the ingredient list of their UV cured gel-polishes for TPO and dispose of them if they do.
They also need to confirm with suppliers that future stock will not contain TPO.
Industry reactions
The Cosmetic, Toiletry and Perfumery Association (CTPA) said in a statement that the ban on the ingredient in the EU “is based on extreme caution and does not mean that current cosmetic products containing TPO are unsafe”.
Caroline Rainsford, Director of Science at the UK trade association CTPA, commented: “The reason why TPO has been banned in cosmetic products in the EU is based on its hazardous properties, meaning how a substance might behave under a ‘worst case’ situation when our bodies are exposed to a very large amount.
“This is not how TPO is used in cosmetics.
“The amount of this ingredient used in nail products is over a thousand times less than the amount which could have any negative effect on fertility and these products are applied to the nail, so the potential for the ingredient to be absorbed into our bodies is even smaller.
“All these factors are taken into account through the legally required, robust safety assessment which all cosmetic products must undergo before being sold, by a duly qualified and experienced safety assessor.”