TPO in gel nail polishes: why the EU and UK have banned it

For years, it remained hidden inside an INCI name that no one pronounces. Then, within twelve months, TPO became the most discussed acronym in salons: banned in cosmetics in the European Union from September 1, 2025, and banned in new products placed on the market in Great Britain from August 15, 2026.

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The news produced two opposing narratives. In the first, every gel manicure would suddenly be toxic. In the second, the ban would be mere bureaucracy and mean nothing. Neither interpretation accurately explains what happened.

The problem is that three different things have been mixed together: an ingredient, a product category, and a legal classification. They need to be distinguished; otherwise, people end up fearing the lamp and blindly trusting a label.

Why gel conquered the manicure

Gel manicures meet a very specific desire: glossy color, an even surface, and longer wear than traditional nail polish. The difference comes from the way the formula transforms.

Classic nail polish dries mainly through solvent evaporation. A gel, on the other hand, contains a system of monomers and oligomers that, when exposed to light from a compatible UV or LED lamp, polymerizes and forms a solid network. Photoinitiators are needed to start the reaction: molecules capable of absorbing light energy and triggering curing.

TPO — listed as Trimethylbenzoyl Diphenylphosphine Oxide, CAS number 75980-60-8 — is one of these photoinitiators. It was valued because it enables efficient polymerization and performs well even with the most opaque colors, where light struggles to reach deep into the product. However, it is not the only system available: many formulas were already TPO-free, and others have been reformulated with different photoinitiators.

The distinction is essential. The authorities did not ban gel manicures, lamps, or all photoinitiators. They banned one specific substance in cosmetic formulations.

How the ban came about

The story did not begin with a viral post, nor in 2025. It is the result of a sequence of events spanning years.

From the old safety opinion to the new classification

In 2015, the European Scientific Committee on Consumer Safety, the SCCS, assessed TPO and concluded that, under the conditions examined at the time, it could be considered safe at concentrations of up to 5% in certain professional UV nail gels. That opinion is often cited as though it contradicted the current ban.

In fact, it addressed a different question, using the data and classification available at that time. In the following years, new assessments of reproductive toxicity emerged. In September 2021, the Committee for Risk Assessment of the European Chemicals Agency adopted an opinion supporting a more severe classification, subsequently formalized by Delegated Regulation (EU) 2024/197.

TPO thus entered the Repr. 1B category: a substance presumed toxic to human reproduction based on the body of evidence established by the European system. The harmonized indication is H360Fd, “may damage fertility; suspected of damaging the unborn child.”

Precision is needed here, because online the acronym CMR—carcinogenic, mutagenic, or toxic for reproduction—has conflated very different categories. TPO was not banned because it was classified as carcinogenic. It was banned because of the third letter of the acronym.

Why a classification has automatic consequences

The European Cosmetics Regulation generally prohibits substances classified as CMR category 1A or 1B, unless an exemption is obtained by meeting highly stringent conditions and is accompanied by a favorable SCCS assessment for the specific use. It is the same mechanism I described regarding the new CMR rules arriving at the pharmacy counter.

No derogation request with an updated dossier was submitted for TPO. Regulation (EU) 2025/877 therefore included it in Annex II, the list of substances prohibited in cosmetics. As of September 1, 2025, in the European Union, it is no longer permitted to place on the market or make available cosmetic products containing it.

The Commission also clarified a point that had caused confusion in salons: in the EU, there is no window for using up old stocks. After that date, a professional may not use a product containing TPO on a client, even if it was lawfully purchased before the ban.

What changes in Great Britain from 15 August 2026

Outside the European Union, the dates do not coincide. In Great Britain — England, Scotland and Wales — Statutory Instrument 2026 No. 23, adopted in January 2026, added TPO and fifteen other CMR substances to the list of substances prohibited in cosmetics. The ban on placing new products on the market took effect on 15 August 2026.

However, there is a transition that the EU had not granted. Products already lawfully placed on the British market before that date may continue to be made available until 14 February 2027: after that, distributors and retailers may no longer sell them, and professionals may no longer purchase them.

There is a further difference, and it is the one that matters most in everyday practice. According to the interpretation of the British cosmetics industry association, agreed with trading standards authorities, professionals in Great Britain may continue to use stocks already purchased even after February 2027, until they run out. This has never been possible in the EU. Same substance, two transition philosophies.

Northern Ireland is a separate case: under the product rules applicable within the framework of the Windsor Framework, it follows the European Union’s cosmetics regime and therefore the EU ban from 1 September 2025.

For people who travel or shop online, this geography matters. The same product may have a different status depending on the market and the date on which it entered the supply chain. “It is still on sale” does not mean the rule is false: it may indicate a legal transition, a different market, or, naturally, a non-compliant offering.

Hazard and risk: the distinction that avoids slogans

TPO classification describes a hazard: the inherent ability of a substance to produce a harmful effect under the conditions considered in toxicological tests. The risk to an individual also depends on the dose, route and duration of exposure, frequency, and how the product is used.

This distinction is not intended to minimize the ban. It is meant to explain why two statements can both be wrong: “if it is banned, one manicure causes infertility” and “if it has not been demonstrated in clients, then there is no problem at all.” The first turns a regulatory classification into an individual diagnosis. The second ignores the principle by which cosmetics regulations manage substances classified as having serious effects.

The basis for the classification concerns toxicological and reproductive data, not a study that measured infertility after occasional manicures. Neither the European decision nor the British one demonstrates that a single application caused fertility damage in people. At the same time, when a substance enters such a stringent legal category, the law requires a specific justification for keeping it in cosmetics—and for TPO, that justification was never requested.

The ban, therefore, is not a retroactive medical bulletin for people who have worn gel in the past. It is a risk-management decision based on a new classification.

“The most interesting test is not the size of the words ‘free from.’ It is the quality with which a formula has been redesigned, tested, and explained.”

“TPO-free” is useful, but it does not say everything

The new claim addresses a real need: it allows salons and clients to identify formulas that comply with the rule. If truthful, “TPO-free” is simple and useful composition information.

The problem arises when we attribute meanings to it that it does not have. A TPO-free product is not automatically:

• free from all photoinitiators;
• free from HEMA or other (meth)acrylates;
• hypoallergenic;
• does not need to be properly cured;
• gentler for everyone;
• usable with any lamp.

Reformulation does not mean removing one word from the INCI. Changing the photoinitiator system can alter the speed and depth of polymerization, color stability, compatibility with the lamp, and the amount of unreacted material. It is the finished formula, under its conditions of use, that must be assessed—not the absence of a single line.

That is why it makes little sense to improvise combinations of gels and lamps simply because a product carries a new claim. The exposure time and wavelength specified by the formulator are part of the system, just like the product itself.

The distinct issue of acrylate allergies

Something does not add up in the way gel safety is discussed: while TPO is at the center of a decision concerning reproductive toxicity, much of the harm actually observed involves something else—sensitization to (meth)acrylates. This happens especially when uncured product touches the skin or when the lamp does not cure it completely.

HEMA and Di-HEMA Trimethylhexyl Dicarbamate are not synonyms for TPO. In the EU, they are permitted in nail products only for professional use and must carry specific warnings. An analysis published in 2024 of 394 nail cosmetics available for online purchase found HEMA in 58% of products, Di-HEMA in 34%, and at least one of the two in 67%. This is a snapshot of that sample and market, not a universal estimate; it nevertheless shows how easy it is to confuse different chemical issues under a single “safe gel” label.

Allergic contact dermatitis may manifest as itching, swelling, redness, blisters, cracking, or nail lifting. Symptoms may also sometimes appear on the eyelids, face, or neck through transfer by the hands. The British Association of Dermatologists points to a particular risk with home kits, when the gel comes into contact with the skin or curing is insufficient.

Avoiding skin contact with uncured product, following the instructions, and using a compatible lamp therefore remain valid precautions even in a TPO-free world. If a reaction is suspected, continuing to try different formulas on your own only complicates the situation: it is more prudent to stop and seek a medical or dermatological evaluation.

How to check a gel without becoming a chemist

For those who do not work with formulas, the check can remain simple. Four steps, in order of usefulness.

1. Look for the exact INCI name

The name to look for is Trimethylbenzoyl Diphenylphosphine Oxide. “TPO” is the technical abbreviation, but the label normally lists the full INCI name.

2. Ask the salon which formula is being used

A reliable answer does not require absolute promises. It is enough for the professional to know how to identify the product, the market it is intended for, its ingredient list, and the lamp specified. In the EU, after September 1, 2025, the presence of old stock does not make its use on a client legitimate.

3. Do not use the claim as a universal shortcut

TPO-free answers the question “does it contain TPO?” Allergies, lamp compatibility, and proper application require different questions. “HEMA-free” also does not mean “free of all acrylates” and does not guarantee the absence of sensitization.

4. Protect skin and nails with practical steps

Don't peel off gel with your fingers, don't leave liquid product on the skin, and take breaks when your nails are fragile. To protect the skin from exposure during lamp use, the American Academy of Dermatology recommends a broad-spectrum, water-resistant sunscreen with SPF 30 or higher on the hands, or opaque, dark-colored fingerless gloves.

How I see it

I watch with curiosity as the market turns a technical change into an immediately recognizable claim. It's useful when it helps people choose a compliant product. It becomes less useful when a single absence is presented as synonymous with complete safety.

There's also a lesson that goes beyond nails and concerns cosmetics as a whole. A favorable safety opinion from 2015 was superseded by a 2024 classification. Not because science had lied, but because the data, questions, and regulatory thresholds had changed. It's the same misunderstanding I described when discussing the fear of chemicals extending to sunscreens: a revision is portrayed as a confession, when it's maintenance.

And there's a point that concerns me personally, because it's why we chose a single sales channel. Faced with news like this, the right question isn't “what should I avoid?” but “who can I ask?” Pharmacies that distribute LeLang receive communications about formula changes before the product reaches the shelf, and the person behind the counter is trained to read an INCI rather than repeat a claim. On a marketplace, that conversation doesn't exist: there's a product listing and a large headline.

One less acronym, more of the right questions

The TPO ban doesn't bring the gel manicure era to an end. It accelerates a reformulation already underway and moves the United Kingdom and the European Union toward a substantially aligned framework, with different timelines.

The most useful lesson isn't to fear every lamp or trust every “free-from” label. It's to distinguish the ingredient's name from the product category, hazard classification from individual risk, regulatory compliance from tolerability, and TPO from acrylate allergies.

You can't judge a manicure by a single acronym. But an acronym can be the starting point for asking for traceable formulas, compatible tools, and more precise information.