The United Kingdom has introduced new restrictions on a chemical commonly used in some gel nail polishes amid concerns over its potential impact on fertility and reproductive health.
The restriction targets trimethylbenzoyl diphenylphosphine oxide, commonly known as TPO, a photoinitiator that enables gel polish to harden when exposed to UV light and helps improve its durability and colour retention.
Under the new rules, which took effect on Saturday across England, Wales and Scotland, manufacturers are no longer permitted to place new TPO-containing cosmetic products on the UK market. 
However, beauty salons have been given until February 14, 2027, to stop using existing products containing the chemical, meaning customers could still encounter TPO-based gel polishes during the transition period.
The move follows concerns arising from animal studies that have linked TPO exposure to possible reproductive and fertility problems. The European Union introduced a similar prohibition in September 2025.
The restrictions have nevertheless attracted debate within the cosmetics industry. The Cosmetic, Toiletry and Perfumery Association has maintained that the concentration of TPO used in nail products is significantly lower than levels associated with harmful effects.
The UK decision is therefore expected to intensify discussions within the beauty industry over whether precautionary restrictions should take priority where potential reproductive risks remain under investigation.
