TPO Gel Polish Ban: What It Means for US Manicures
The TPO gel polish ban: the EU prohibited TPO in all cosmetics from Sept 1, 2025 over rat fertility data. It is still legal in the US. What to check.
The TPO gel polish ban is an EU rule: since September 1, 2025, trimethylbenzoyl diphenylphosphine oxide (TPO), the photoinitiator that hardens many gel polishes under a UV or LED lamp, cannot be sold or used in any cosmetic in the European Union. The reason was a reproductive-toxicity classification based on rat studies. TPO is still legal in the United States.
What is TPO in gel nail polish?
TPO is a photoinitiator: a molecule that absorbs UV or visible violet light and splits into free radicals that start the gel’s acrylate monomers joining into a hard plastic film. Its full chemical name is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, its INCI label name is Trimethylbenzoyl Diphenylphosphine Oxide, and its CAS number is 75980-60-8.
The EU’s Scientific Committee on Consumer Safety (SCCS), the independent panel that assesses cosmetic ingredient safety for the European Commission, reported that gel products used TPO at 0.5% to 5.0%. During curing, TPO is consumed: its fragments become chain ends inside the polymer. That is why the curing step matters for exposure, and why a gel that stays tacky or soft after the lamp is worth fixing (lamp mismatch and under-curing are also common causes of gel manicures lifting early).
Why did the EU ban TPO in gel polish?
The EU banned TPO because it was reclassified as a CMR substance, category 1B (toxic for reproduction), and EU cosmetics law automatically prohibits CMR 1A and 1B substances unless a company requests and wins an exemption. Nobody requested one for TPO.
The sequence, from the regulator texts:
- 2012: TPO was first classified as a category 2 reproductive toxicant (suspected of damaging fertility). That would have banned it from cosmetics by December 2013.
- March 27, 2014: Industry sought an exemption, and the SCCS concluded in opinion SCCS/1528/14 that TPO was “safe when used as a nail modelling product at a concentration of at maximum 5.0%,” while flagging it as a moderate skin sensitizer. The EU then allowed it only for professional use in artificial nail systems, at up to 5% (Annex III, entry 311).
- Harmonised reclassification: ECHA’s Risk Assessment Committee, the EU chemicals agency’s scientific committee, reviewed the evidence, and Delegated Regulation (EU) 2024/197 upgraded TPO to category 1B, applying from September 1, 2025.
- May 12, 2025: Regulation (EU) 2025/877 deleted entry 311 and added TPO to Annex II, the prohibited list, from the same date. The European Commission’s Q&A reports the member-state vote as 25 in favour, 1 against and 1 abstention.
The Commission’s Q&A is explicit that the old SCCS safety opinion no longer applies once a substance is CMR 1B, unless a new exemption request triggers a new assessment. On salons, it states that professionals cannot use TPO products on clients from September 1, 2025, adding: “This applies regardless of whether the product was purchased before the cut-off date.”
Why is TPO bad? What the animal studies found
TPO’s concern is male fertility in rats at high oral doses, not a measured effect in people. The 2014 SCCS opinion summarizes the studies that drove the classification:
- In a 28-day study, Sprague-Dawley rats given 750 mg per kg of body weight per day by stomach tube developed testicular atrophy, plus kidney and liver effects at 250 mg/kg and above. Testis and liver findings persisted after a recovery period.
- In 90-day studies in Wistar rats, males at 1,000 mg/kg/day had atrophy of the sperm-producing tubules and low or absent sperm in the epididymis. The no-observed-adverse-effect level (NOAEL), the highest dose with no adverse effect, was 100 mg/kg/day.
- TPO was negative in bacterial and mammalian cell mutation tests, and no carcinogenicity data existed.
- In a mouse lymph node assay, TPO was a moderate skin sensitizer (EC3 of 27%).
A category 1B label means regulators judged the animal evidence strong enough to presume a human hazard. It is a statement about what the chemical can do at sufficient dose, not a measured risk from a manicure. Cosmetic chemist Kelly Dobos of the University of Cincinnati put the gap plainly in a September 2025 university interview: the end points came from animal-feeding studies, and “You’re not eating the nail polish.”
Is gel polish toxic? What the exposure math says
For a fully cured manicure, the SCCS’s 2014 worst-case estimate left a wide safety margin. Its calculation, reproduced here, is the clearest way to see how far a manicure sits from the rat doses:
| Step in the SCCS 2014 calculation | Value |
|---|---|
| Gel applied, full fingernail and toenail set | 4 g |
| TPO in the gel (EU maximum at the time) | 5% |
| TPO applied | 200 mg, about 3.33 mg/kg for a 60 kg adult |
| Assumed residue left uncured | 1% |
| Assumed absorption of that residue through the nail | 100% (deliberately worst case) |
| Systemic exposure | 0.033 mg/kg body weight per day |
| Rat NOAEL, halved for 50% oral absorption | 50 mg/kg/day |
| Margin of safety (NOAEL divided by exposure) | 1,515 |
Two further data points in the opinion support a small real exposure. An extraction test on cured gel containing 2.16 to 2.34 mg of TPO per nail recovered less than 0.2% of it. And in a 2010 repeated patch test, 51 women completed applications of a gel with 2.6% TPO to the nails, with no irritation or allergy reactions at induction or challenge (the SCCS noted such tests cannot rule out sensitizing potential).
The weak points are skin contact and home use. The SCCS noted that careless application can put uncured gel on the cuticle and side walls, and that home applications “may cause more accidental skin contact” than professional ones. Uncured gel on skin is the route for allergy, which is the more common problem.
Is TPO banned in the US?
No. As of October 7, 2026, TPO is not one of the 10 entries on FDA’s list of prohibited and restricted cosmetic ingredients (that page was last updated in February 2022), and FDA states that cosmetic ingredients other than color additives “do not need FDA approval before they go on the market.”
The Modernization of Cosmetics Regulation Act of 2022 (MoCRA) did not change that for TPO. According to FDA’s MoCRA page, the law requires facility registration, product listing with ingredients, reporting of serious adverse events within 15 business days, and records supporting the safety of each product. It did not create an EU-style automatic ban for reproductive toxicants.
| Question | European Union | United States |
|---|---|---|
| Legal status of TPO in nail gels | Prohibited in all cosmetics from Sept 1, 2025 | Allowed; no federal restriction |
| Rule that applies | Regulation 2025/877, Annex II | FD&C Act as amended by MoCRA (2022) |
| What triggers a ban | Automatic for CMR 1A/1B substances unless an exemption is granted | No automatic hazard-based trigger; FDA list has 10 entries |
| Status before the ban | Professional use only, artificial nail systems, max 5% | No concentration limit |
| Existing salon stock | Must stop being used or sold; no transition period | Can be used and sold |
| TPO-L and TMO | Different substances, not covered by the TPO ban | Allowed |
Brands that sell in both markets have had to make TPO-free versions for the EU. In the US, gels with and without TPO can both be sold.
What are the real side effects of gel polish?
The documented side effect is allergic contact dermatitis from acrylates and methacrylates, the monomers that form the gel itself. Allergic contact dermatitis is a delayed immune rash, often itchy, red and blistering, that appears where an allergen touched skin, or sometimes elsewhere, such as the eyelids and face.
The numbers come from large patch-test networks:
- Europe, 2013-2015: In 11 clinics of the European Environmental Contact Dermatitis Research Group, 136 of 18,228 tested patients (0.75%) had allergy caused by nail acrylates, which made up 67.3% of all acrylate allergy cases. 43.4% were consumers rather than nail technicians; 88.9% had hand lesions and 36.8% facial lesions. 92.5% reacted to HEMA (2-hydroxyethyl methacrylate) (Gonçalo et al., Contact Dermatitis, 2018).
- North America, 2001-2016: Of 38,775 patients tested by the North American Contact Dermatitis Group, 769 (2.0%) had contact dermatitis associated with nail care products. The face (43.0%) and hands (27.6%) were the main sites, HEMA was positive in 56.6% of those tested for it, and HEMA allergy increased significantly over the period (Warshaw et al., Dermatitis, 2020).
Allergy shows up as itching or rash around the nail folds, fingertips, eyelids or face. Most patients in the European study reacted to two or more acrylates, so switching gel brands often does not help. If a rash appears after manicures, a board-certified dermatologist can patch test to identify which acrylate is responsible. Repeated removal also thins nails; see why nails peel in layers for that separate problem.
How do I read a gel polish label for TPO?
Look at the full ingredient list (INCI names) on the bottle, box or brand site, not only at front-label claims such as “TPO-free” or “HEMA-free.” The names to know:
| INCI name on the label | Common name | What it is | Status as of Oct 7, 2026 |
|---|---|---|---|
| Trimethylbenzoyl Diphenylphosphine Oxide | TPO | Photoinitiator | Banned in EU cosmetics; legal in US |
| Ethyl Trimethylbenzoyl Phenylphosphinate | TPO-L | Liquid photoinitiator, a different molecule | Not covered by the EU TPO ban |
| (2,4,6-trimethylbenzoyl) bis(4-methylphenyl)phosphine oxide | TMO | Photoinitiator, a different molecule | Not covered by the EU TPO ban |
| Hydroxyethyl Methacrylate | HEMA | Monomer | Allowed; the most frequent nail acrylate allergen in both studies above |
| Hydroxypropyl Methacrylate | HPMA | Monomer | Allowed; 88.6% of European nail-acrylate allergy patients reacted |
| Glycol Dimethacrylate | EGDMA | Cross-linking monomer | Allowed; 69.2% reacted in the same study |
Every gel that cures under a lamp needs some photoinitiator, so “TPO-free” means a different one was used, not that the gel has none. Norway’s food safety authority warns that TPO should not be confused with similarly named substances such as TPO-L and TMO. A “HEMA-free” label still leaves other methacrylates, and most allergic patients in the European study reacted to more than one.
What is the evidence behind these claims?
The evidence ranges from rat feeding studies to regulator texts and large patch-test networks. Here is how each claim stands.
| Claim | Best evidence | Study type, size, duration | Strength |
|---|---|---|---|
| High oral doses of TPO harm male fertility in rats | Rat studies summarized in SCCS opinion SCCS/1528/14, 2014 | 28-day and 90-day oral studies in rats; testicular atrophy at 750 and 1,000 mg/kg/day, NOAEL 100 mg/kg/day | Lab-only |
| A full gel set at 5% TPO leaves a wide margin of safety | SCCS opinion SCCS/1528/14, 2014 | Worst-case exposure calculation for a 4 g full set; margin of safety 1,515 | Guidance |
| TPO is prohibited in all EU cosmetics | Commission Regulation (EU) 2025/877 | Regulation following the CMR 1B classification, applying from September 1, 2025 | Guidance |
| Nail acrylates are a leading cause of acrylate allergy | Gonçalo et al., Contact Dermatitis, 2018 | Patch testing of 18,228 patients in 11 European clinics, 2013-2015; 136 (0.75%) with nail-acrylate allergy | Limited |
| Nail care products are linked to contact dermatitis in North America | Warshaw et al., Dermatitis, 2020 | Patch testing of 38,775 patients by the NACDG, 2001-2016; 769 (2.0%) with nail-product dermatitis | Limited |
What should US clients and salons do now?
No regulator advises removing existing manicures or avoiding gel; the practical moves are about skin contact and curing:
- Choose by the label if you want to avoid TPO. Look for the absence of Trimethylbenzoyl Diphenylphosphine Oxide in the INCI list. A gel sold as EU-compliant after September 2025 should not contain it.
- Keep uncured gel off skin. Ask for clean cuticle margins; at home, wipe any flooded gel before curing. This matters more for allergy than which photoinitiator is used.
- Cure fully with the lamp the brand specifies. Under-cured gel leaves more unreacted monomer and photoinitiator. For lamp exposure itself, see whether UV nail lamps are safe.
- Salons serving EU-trained clients or selling online to Europe: products shipped into the EU must be TPO-free, and the Commission says there is no grace period for existing stock.
- Technicians: the European study found most occupational cases developed in the first year of work and at least 11.7% had to leave their jobs, so gloves and keeping uncured product off the skin are the main protection.
Sources and research notes
Commission Regulation (EU) 2025/877 (recitals and Article 2), the European Commission TPO questions and answers on stock and professional use, the full 2014 SCCS opinion SCCS/1528/14 with its rat toxicity, exposure and patch-test data, the Norwegian Food Safety Authority TPO page on TPO-L and TMO, FDA prohibited-ingredient and MoCRA pages, and two large patch-test studies of nail acrylate allergy, checked on the date shown.
Source record date: 2026-10-07. Prices and availability are as of that date.
- Commission Regulation (EU) 2025/877 of 12 May 2025 amending Regulation 1223/2009 on CMR substances (TPO to Annex II, applies from 1 September 2025)
- European Commission: TPO in nail products, questions and answers (no transition period, professional use, 25-1-1 vote)
- SCCS opinion on Trimethylbenzoyl diphenylphosphine oxide (TPO), SCCS/1528/14, adopted 27 March 2014
- Norwegian Food Safety Authority (Mattilsynet): Trimethylbenzoyl Diphenylphosphine Oxide (TPO), TPO-L and TMO not covered
- FDA: Prohibited and restricted ingredients in cosmetics (10 entries, TPO not listed; page updated 02/25/2022)
- FDA: Modernization of Cosmetics Regulation Act of 2022 (MoCRA) requirements
- Gonçalo M et al. Allergic contact dermatitis caused by nail acrylates in Europe. An EECDRG study. Contact Dermatitis 2018;78:254-260 (n=18,228, 2013-2015)
- Warshaw EM et al. Contact dermatitis associated with nail care products: NACDG data 2001-2016. Dermatitis 2020;31:191-201 (n=38,775)
- University of Cincinnati News: Europe bans chemical used in some gel nail polishes (Kelly Dobos interview, 4 September 2025)
Frequently asked questions
Is TPO banned in the US?
No. As of October 7, 2026, trimethylbenzoyl diphenylphosphine oxide (TPO) is not on FDA's list of prohibited or restricted cosmetic ingredients, and the 2022 MoCRA law added registration, listing, adverse-event and safety-record duties rather than an ingredient ban. US salons can legally use TPO gels.
Why is TPO bad?
In rat studies, high oral doses of TPO caused testicular atrophy and reduced sperm. That led the EU to classify it as toxic for reproduction, category 1B, which automatically bans a substance from EU cosmetics. No study has measured harm in people from gel manicures.
Is TPO-L the same as TPO?
No. TPO-L is ethyl trimethylbenzoyl phenylphosphinate, a different photoinitiator. Norway's food safety authority states that TPO-L and TMO are not covered by the EU TPO ban; check the full ingredient list for the exact INCI name.
Should I remove my gel nails because of the TPO ban?
There is no regulatory advice to remove existing gel nails. The 2014 EU safety opinion estimated a 1,515-fold margin of safety for a full set at 5% TPO, and the ban followed a hazard classification, not a new finding of harm from worn manicures.
What is the most common side effect of gel polish?
Allergic contact dermatitis to acrylates, especially HEMA. In a European study of 18,228 patch-tested patients from 2013 to 2015, nail acrylates caused 136 allergy cases, and 92.5% of those patients reacted to HEMA.
Can US salons still buy TPO gels?
Yes. There is no federal US restriction, so TPO gels remain on sale. Products sold in the EU have had to be TPO-free since September 1, 2025, so brands selling in both markets have made TPO-free versions.