How Do I Know If My Gel Polish Has TPO in It? The Label-Reading Guide

By S. C. Aris — about the author

Last updated: 26 July 2026

Why everyone is suddenly asking this

On 1 September 2025 the European Union prohibited trimethylbenzoyl diphenylphosphine oxide — TPO — in all cosmetic products, gel nail polish included. The European Commission’s own Q&A on the prohibition sets out the mechanics: TPO was given a harmonised classification as a category 1B reproductive toxicant under Commission Delegated Regulation (EU) 2024/197, and because Article 15(2) of the EU Cosmetics Regulation automatically bans CMR 1A and 1B substances from cosmetics, TPO had to be added to Annex II (the prohibited list) by Commission Regulation (EU) 2025/877 from the same date.

Two details from that document are worth holding on to, because most coverage skips them. First, the Commission states it had no discretion — the ban was automatic once the classification applied, and nobody submitted a derogation request. Second, there is no sell-through or use-up period: EU salons could not finish existing bottles, even ones bought legally months earlier.

Then the headlines arrived — CNN reported the ban under the phrase “reproductive toxicant” — and millions of people looked at the bottle on their bathroom shelf and had no idea how to check it. That is the question this page answers.

The 60-second TPO check

Work through these in order. Stop as soon as you get a definite answer.

1. Find the ingredient list. On a retail gel it is on the bottle, the box, or a peel-back label. The US Food and Drug Administration requires cosmetics sold at retail to carry an ingredient declaration in descending order of predominance — and notes that this requirement still applies to products marked “For professional use only” if they are also sold at retail (FDA, Nail Care Products). Salon-only and free-sample products may legitimately have no list.
2. Search for the exact words “Trimethylbenzoyl Diphenylphosphine Oxide.” That is the INCI name. Some brands print the systematic form instead: Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. Both mean the same molecule.
3. If a CAS number is printed, check it against 75980-60-8. This is the single most reliable test, because CAS numbers cannot be marketed around. It is the number written into law: Great Britain’s statutory instrument lists entry 1745 as “Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 75980-60-8, 278-355-8” (SI 2026/23, Schedule).
4. Beware the near-misses. If you see TPO-L, BAPO, or trimethylolpropane triacrylate, that is not the banned substance. See the decoder table below.
5. No list on the bottle? Ask the brand for the ingredient declaration or safety data sheet in writing. Since September 2025 almost every serious gel manufacturer has published a TPO status statement, because they had to reformulate for the EU market anyway. A brand that cannot answer this in 2026 is telling you something.

The decoder table: what is actually TPO, and what only sounds like it

This is where most articles — and a great deal of confident salon advice — go wrong. Several photoinitiators and acrylate monomers sit in adjacent chemical families and get called “TPO” loosely. Only one of them is the substance regulators prohibited.

The one-line rule: the letters “TPO” on a marketing page prove nothing. The words diphenylphosphine oxide — or the number 75980-60-8 — prove everything.

Where TPO is banned, and from exactly when

Your answer to “does this matter for me?” depends entirely on which market you buy in. The dates below come from the legislation itself rather than from press summaries, because the summaries disagree with each other.

The Great Britain position is the one almost every article gets muddled, so it is worth stating plainly: GB has a staggered ban with a genuine sell-through window, which is the opposite of the EU’s abrupt cut-off. A bottle that a GB salon legally holds in autumn 2026 may still be legally used there for some months — and would have been illegal in Dublin or Berlin a year earlier.

So does it matter if you are in the US?

This is the honest part, and it is where a page that only wanted your click would either panic you or dismiss you.

The US regulatory system is structurally different, not merely slower. As the FDA states, “cosmetic products and ingredients, including nail products, do not need FDA approval before they go on the market, with the exception of most color additives” — products must be safe when used as directed, and the agency acts after the fact against products that are not (FDA). The EU system, by contrast, bans CMR-classified substances automatically and by formula. The EU ban was therefore triggered by TPO’s hazard classification, not by any finding that manicures had harmed anyone.

That distinction matters for how worried to be. As Chemistry World reported, the category 1B classification is “presumed” reproductive toxicity based largely on animal data. Caroline Rainsford, director of science at the UK Cosmetic, Toiletry and Perfumery Association, told the magazine that the classification reflects hazard under a worst-case exposure, adding: “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.”

Against that, the Commission’s own position is that the earlier reassurance no longer stands on its own. The Scientific Committee on Consumer Safety had concluded in 2015 that TPO was safe in certain professional UV-cured nail gels up to 5%; the Commission notes that this opinion predates the upgrade from category 2 to category 1B and therefore “no longer applies unless updated” via a fresh assessment. Typical concentrations in gels run between 0.5% and 5%, with a full set of fingernails and toenails using 2–4 g of gel.

Both things can be true: the exposure from a manicure is small and applied to a keratin plate rather than to skin, and Europe’s precautionary framework does not weigh exposure once a substance is classified 1B. If you are pregnant, trying to conceive, or a nail technician with daily occupational exposure rather than fortnightly consumer exposure, choosing a reformulated product is a reasonable, low-cost decision. If you had a gel manicure in 2024, there is nothing in the record to suggest you should be alarmed.

The bit almost nobody explains: cured versus uncured

A photoinitiator has one job. It absorbs light, splits, and starts the chain reaction that turns liquid resin into hard polymer. TPO is a Norrish Type I initiator, meaning it cleaves cleanly under UV/LED light — which is exactly why it was popular, along with a broad absorption range and less yellowing in the cured film.

The practical consequence is that a properly cured gel has consumed most of its initiator, and whatever remains is locked inside a solid polymer bonded to the nail plate. The FDA makes the general version of this point about nail chemistry: some nail ingredients “are harmful when swallowed, but not when used on the nails, because the nail is a barrier, which prevents absorption.”

Which points at the real, practical risk in gel manicures — and it is not the one in the headlines. Under-curing is the problem. Weak or aged lamps, the wrong lamp for the gel chemistry, coats applied too thickly, or product flooding the cuticle and side walls all leave uncured monomer in contact with skin. That is the mechanism behind the acrylate contact allergies nail techs and frequent gel wearers actually develop. Using a TPO-free gel badly is worse than using a TPO gel well.

Four things that reduce real-world exposure, whatever your gel contains

• Keep product off skin. Leave a hairline margin at the cuticle and side walls. Wipe any flood-over before curing, not after.
• Cure with the lamp the gel was designed for, for the full time. Mismatched wavelengths are a leading cause of under-cure; lamp bulbs also lose output with age.
• Thin coats, fully cured, beat thick coats. Light has to reach the bottom of the layer.
• Do not pick or peel gel off. Peeling takes layers of nail plate with it — the single biggest cause of the thin, bendy, damaged nails people blame on the gel chemistry itself.

What TPO-free does not fix

Switching to a reformulated gel changes one molecule in the bottle. It does not change what the process does to the nail plate: the surface abrasion before application, the long occlusion under a rigid film, and the acetone soak-off that strips lipids out of keratin. That is why nails so often emerge from a gel cycle looking chalky, ridged, thin and prone to splitting — and why the fix belongs to aftercare, not to the polish.

It is also worth knowing that the traditional “strengthener” answer can make things worse. The FDA notes that formaldehyde in nail hardeners bonds with the keratin in the nail, but that “using these nail hardeners often, however, may make nails brittle and more likely to break or peel”. Harder is not stronger. We covered that paradox in detail in does nail hardener actually weaken your nails, and the recovery routine in how to repair damaged nails after gel or acrylic removal.

Frequently asked questions

How do I know if my gel polish has TPO in it?

Read the ingredient list and look for “Trimethylbenzoyl Diphenylphosphine Oxide” or “Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide”, or the CAS number 75980-60-8. If the exact name or that CAS number is absent, the product does not contain the banned photoinitiator. If the bottle carries no ingredient list — which is permitted for genuinely salon-only products — ask the manufacturer for the declaration or safety data sheet in writing.

Is TPO the same as TPO-L?

No. TPO-L (ethyl (2,4,6-trimethylbenzoyl) phenyl phosphinate) is a chemically related but distinct substance with its own CAS number, and it is not the substance named in the EU prohibition or in Great Britain’s SI 2026/23. Many brands moved to TPO-L or to BAPO when they reformulated. The letters look almost identical on a label, so check the full chemical name rather than the abbreviation.

Is TPO banned in the United States?

No. TPO remains legal in US nail products. Under US law, cosmetic ingredients other than most colour additives do not require FDA approval before going on sale; products must be safe when used as directed, and the FDA acts against non-compliant products after the fact. The EU ban followed automatically from a hazard classification under a different legal framework.

Can I still use the gel polish I already own?

In the US, yes — there is no restriction. In the EU, professionals may not use TPO-containing products on clients regardless of when the product was bought, because professional use counts as making the product available in the course of commercial activity. In Great Britain, products placed on the market before 15 August 2026 may continue to be made available until the end of 14 February 2027 under the transitional provisions of SI 2026/23. Salon owners should treat this as a summary, not legal advice, and check current guidance for their own market.

Does TPO survive in the cured gel on my nails?

A photoinitiator is consumed as it triggers the curing reaction, and any residue is bound within a solid polymer film sitting on the nail plate. The more meaningful issue is under-curing, which leaves uncured monomer in contact with skin around the cuticle and side walls — the recognised route for acrylate contact allergy. Full cure times, the correct lamp, thin coats and keeping product off the skin matter more in daily practice than which photoinitiator is in the bottle.

Will switching to TPO-free gel stop my nails feeling thin and weak?

Not on its own. Thin, bendy, peeling nails after gel come from the mechanical and solvent side of the process — surface abrasion, acetone soak-offs, and above all picking gel off — rather than from the photoinitiator. Gentle removal, no peeling, and a water-free lipid concentrate worked into the plate and cuticle daily do far more for how nails look and behave than a change of curing chemistry.

Related reading

• How to repair damaged nails after gel or acrylic removal
• Does nail hardener actually weaken your nails? The formaldehyde paradox
• Do nails really need to breathe? The truth about polish breaks
• Why are my nails so weak and brittle — and what actually helps?
• Should you buff the ridges out of your nails?
• Why won’t my nails grow past a certain length?

Sources

1. European Commission, Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs — TPO in Nail Products – Questions & Answers, 7 August 2025 (legal basis, Regulation (EU) 2025/877, Delegated Regulation (EU) 2024/197, no sell-through, professional use, status of the 2015 SCCS opinion).
2. The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026, SI 2026/23 — Schedule, entry 1745 (name, CAS 75980-60-8, EC 278-355-8).
3. SI 2026/23 — Regulation 3, Transitional Provisions (15 August 2026 / 14 February 2027 dates).
4. US Food and Drug Administration — Nail Care Products (pre-market approval, ingredient declaration and “professional use only” labelling, the nail as a barrier, formaldehyde hardeners and brittleness).
5. Chemistry World — Why has the EU banned a key chemical in gel nail products? (Norrish Type I chemistry, 0.5–5% use levels, 2–4 g per full set, EU/Norway/Switzerland scope, CTPA statement).
6. CNN — Europe bans chemical TPO used in some gel nail polishes, 4 September 2025.
7. Scientific Committee on Consumer Safety (SCCS) opinion on TPO in UV-cured nail gels, as characterised and superseded in the European Commission Q&A above.
8. UK Cosmetic, Toiletry and Perfumery Association (CTPA), Caroline Rainsford, quoted in Chemistry World above.

This article is general consumer information about cosmetic ingredients and product labelling. It is not medical advice, and it is not legal or regulatory advice for salon businesses — operators should check the current rules for their own market. Provité Nail Elixir is a cosmetic product intended to support the appearance of the nails; it is not intended to diagnose, treat or prevent any condition. If you have a nail or skin problem that concerns you, speak to a doctor or dermatologist.