London: The UK has introduced new restrictions on trimethylbenzoyl diphenylphosphine oxide (TPO), a chemical used in some gel nail products, after concerns over its potential reproductive health effects. However, the move does not amount to a ban on gel manicures themselves.
Under the new rules, cosmetic products containing TPO can no longer be newly placed on the market in England, Scotland and Wales. Products that were already legally placed on the market can continue to circulate during the transition period, with additional restrictions scheduled to take effect in February 2027.
The development has been widely described as a “gel nail ban” on social media and in some reports, but experts stress that this interpretation is misleading. The regulatory action specifically targets the chemical TPO rather than gel nail treatments as a whole.
What is TPO and why is it used?
TPO, or Trimethylbenzoyl Diphenylphosphine Oxide, is a photoinitiator used in some gel nail formulations.
When gel nail products are exposed to UV or LED light, TPO helps initiate the chemical reaction that causes the liquid product to harden into a durable coating. This curing process is an important part of how many gel manicure systems work.
The chemical is also known as Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide.
According to Dr Ruchi Jain, a fertility specialist at Nova IVF Fertility in Kolkata, TPO is useful as a photoinitiator but has come under regulatory scrutiny following evidence suggesting potential reproductive health effects.
Its classification as a reproductive toxicant has prompted authorities to review its use in cosmetic products, particularly where exposure may occur repeatedly.
Why has TPO raised fertility concerns?
The major concern surrounding TPO comes from its classification as a Reproductive Toxicity Category 1B substance.
This classification is based on toxicological evidence, including experimental studies indicating that exposure to the chemical may affect reproductive function.
According to Dr Jain, studies have reported effects including reduced sperm count, testicular degeneration and impaired reproductive function in males. Experimental findings have also indicated possible disruption of the reproductive cycle in females.
The European Chemicals Agency’s assessment has classified TPO as a reproductive toxicant and also identified it as a skin sensitiser.
However, such a classification identifies a potential hazard and should not automatically be interpreted as proof that routine cosmetic use will cause infertility in humans.
Does getting gel nails cause infertility?
There is currently no evidence that having an occasional gel manicure causes infertility in humans.
This distinction is important because much of the evidence behind the reproductive-toxicity classification comes from controlled toxicological and animal studies.
The level of exposure experienced by a customer during a properly performed manicure may be considerably lower than the exposure levels used in experimental studies. Therefore, the findings cannot simply be translated into a conclusion that someone who gets gel nails will develop fertility problems.
The regulatory concern is instead centred on the potential hazard associated with TPO and the possibility of repeated exposure.
Experts say consumers should therefore avoid interpreting the UK decision as proof that every gel manicure is harmful to fertility.
Nail technicians could face greater exposure
The issue may be more relevant for professional nail technicians who handle gel products frequently as part of their work.
Unlike customers, technicians may be exposed repeatedly while applying, shaping or removing nail products. The level of exposure can depend on the products used, workplace ventilation, handling practices and whether the chemicals come into direct contact with the skin.
Repeated occupational exposure is one reason regulators and experts emphasise safer formulations and appropriate workplace precautions.
Good ventilation, careful handling and minimising direct skin contact can help reduce exposure to chemicals used in nail products.
The UK restrictions are therefore better understood as a chemical safety measure rather than a declaration that gel manicures themselves are unsafe.
UK follows EU action on TPO
The European Union banned TPO in cosmetics from September 2025 after the chemical was classified as a reproductive toxicant.
Great Britain has now introduced its own restrictions covering England, Scotland and Wales.
Under the new UK rules, manufacturers and businesses cannot newly place cosmetic products containing TPO on the market. Products that were already legally placed on the market can remain in circulation during the transition period.
Further restrictions are expected to come into effect in February 2027.
The regulatory changes reflect a broader approach in which cosmetic ingredients identified as potential hazards are reviewed and, where appropriate, replaced with safer alternatives.
Gel nails have another health concern
TPO is not the only chemical in gel nail systems that can cause health concerns.
Many gel nail products contain acrylates and methacrylates, which can trigger allergic contact dermatitis in some people. Repeated exposure can sensitise an individual, meaning that a person may develop a reaction after exposure even to relatively small quantities later.
Symptoms can include:
- Redness and itching around the nails
- Swelling or tenderness of the fingers
- Peeling or cracked skin
- Blisters or skin rashes
- Reactions spreading to the hands, face or neck
These reactions can sometimes occur when uncured or partially cured product comes into contact with the surrounding skin.
For this reason, proper application and curing of gel products are important, particularly for people who frequently undergo gel manicures or work with these products professionally.
Experts call for precautionary approach in India
Dr Jain has supported a precautionary approach towards TPO in India, particularly because the chemical has already received international regulatory attention.
She said regulators should review the use of chemicals in cosmetic products when they have been internationally classified as reproductive toxicants and safer alternatives are available.
Such an approach would focus on reducing unnecessary exposure while allowing regulators to consider the available scientific evidence, product formulations and exposure levels.
For consumers, the UK development is a reminder that a regulatory restriction on one ingredient does not necessarily mean that an entire category of products has been banned or proven dangerous.
The key issue is TPO exposure and the potential hazards associated with the chemical. People who use gel nail products regularly can also pay attention to product ingredients, avoid unnecessary skin contact and seek professional advice if they develop persistent skin reactions.
As countries continue to reassess cosmetic ingredients based on emerging toxicological evidence, the focus is increasingly shifting towards safer formulations that minimise potential risks to both consumers and workers.