What is TPO in nail polish - and why has it been banned?

As of 1^st September 2025, the EU has banned TPO (trimethylbenzoyl diphenylphosphine oxide) from all cosmetics. TPO is used to harden gel polish. It was removed because it was found to harm reproduction in animal testing.  

Is TPO the only problem ingredient in nail polish?

Even without TPO, both gel and regular nail polish – as well as many other cosmetic products - still rely on another toxic and well-documented allergen: acrylates. Acrylates (here including methacrylate monomers, acrylate monomers, and their polymeric forms such as copolymers and cross polymers) are film-formers that make coatings hard, glossy and long-wearing, and they are known skin sensitisers. Dermatology groups flag acrylates as notorious contact allergens.

“But I only react on my face.”

You don’t have to put acrylate laced products on your face directly to experience a reaction. We touch our eyes, lips and cheeks all day. Dermatology guidance explicitly lists nail cosmetics among common triggers for eyelid and peri oral dermatitis, often via hand-to-face transfer. Check out our ingredients cheat sheet which documents other toxic additives in cosmetics and personal care to look out for.

However, acrylates are not confined to nail polish. Clinical reviews and dermatology guidance have flagged that rising acrylate allergies are also linked to waterproof mascara and liquid eyeliner (film-formers for wear) and sunscreens (water-resistance). Symptoms include dermatitis reactions on thin, frequently touched skin, such as lips and eyelids, from hand-to-face transfer. Once sensitised, very small exposures can trigger allergic reactions.

So what should you do?

Look for names like Acrylates Copolymer and Acrylates Crosspolymer on product ingredient lists. Still not convinced? Read our founder's Allergy Story, a three-part series where she documents her years of contact dermatitis reactions triggered by acrylate-laced fake eyelash glue:

• Skip nail polish if you experience any skin sensitivity.

• Read the ingredient lists on your personal care products – especially cosmetics, skincare and sun care.

• Still unsure what’s setting you off? Ask a dermatologist about patch testing for common contact dermatitis allergens.