What is TPO and why was it used?
TPO (trimethylbenzoyl diphenylphosphine oxide) is a photoinitiator that reacts with LED or UV light to cure gel products.
Why techs valued it:
- Fast results with efficient curing
- Broad compatibility with different monomers
- Strong, even cure for thicker layers
- Helps protect color from yellowing
Because of these benefits, TPO became one of the most widely used curing agents in professional gel formulations.
What changed in the EU
On September 1, 2025, the EU reclassified TPO as a CMR 1B substance. That automatically placed it on Annex II of the EU Cosmetics Regulation, which bans its use in cosmetic products.
This is an EU regulatory move, not a global safety consensus. It applies only to products sold or used within the EU.
What about the UK
The United Kingdom has not banned TPO yet. Post-Brexit, the UK operates under its own cosmetics framework, which currently allows TPO.
However, regulators have signaled that a ban is expected in the near future. Industry groups anticipate the UK will follow the EU’s lead by late 2026 or early 2027. For now, TPO gels remain legal in the UK, but salons and suppliers should expect a transition period before the restriction comes into force.
Why there is no need to panic
- The studies behind the EU decision used extremely high animal exposure levels, not real salon practice.
- Once cured, photoinitiators like TPO are locked into the hardened coating, making exposure very low.
- The FDA has not banned TPO. In the U.S., ingredients are permitted unless proven unsafe.
- In most gels, TPO sits around 1 to 2 percent, with some up to 4 percent. Proper curing and avoiding skin contact keep this safe.
- TPO is still used in regulated dental composites in the EU, which shows the difference between regulatory categories and consumer safety.
Bottom line: In the U.S. and Canada, there is no ban and no evidence of risk under normal salon use.
Where Stellar Gel stands
We are a U.S. and Canada company that ships worldwide. Our priority is making sure nail pros everywhere can work confidently with our products.
- All new Stellar Gel products will be TPO-free moving forward
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We already offer HEMA, TPO, and HPMA-free options, which are perfect for sensitive clients and for compliance in stricter markets
👉 View our HEMA/TPO/HPMA-Free collection page
By reformulating without TPO, we stay compliant for EU and future UK markets, while keeping the same performance nail techs expect.
TL;DR
The EU banned TPO in cosmetics starting September 1, 2025. The UK has not banned it yet, but a similar move is expected around 2026–2027. The U.S. and Canada have not banned TPO, and when used properly, it remains safe in salon practice. Stellar Gel is already reformulating new launches without TPO so that pros everywhere can work without worry.