A major new European Union regulation officially took effect on September 1, 2025, banning the use of TPO (trimethylbenzoyl diphenylphosphine oxide) — a common ingredient in gel nail polish. The move has sparked controversy in the beauty industry, particularly because the ingredient remains legal and unregulated in the United States.

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What Is TPO and Why Did the EU Ban It?

TPO is a photoinitiator, the chemical that allows gel polish to harden quickly under UV or LED lamps, giving manicures their glossy, chip-resistant finish.

After reviewing multiple studies, the EU classified TPO as “carcinogenic, mutagenic, or toxic to reproduction.” While large-scale human trials are lacking, animal studies suggest possible links to:

• Reproductive health issues

• Hormonal disruption

• Long-term cellular damage

EU regulators acted under the precautionary principle, banning TPO despite limited direct human data. “It’s more of a precautionary move than a response to conclusive human evidence,” explained dermatologist Dr. Hannah Kopelman.

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A Divided Beauty Industry

The EU first announced its decision in May 2024, but the enforcement date arrived quickly and without exceptions. Until now, TPO was allowed in professional use at concentrations up to 5%. From September 1 onward, any product containing TPO is outlawed.

This sudden change has:

• Left salons scrambling to replace banned products

• Forced businesses to discard costly inventory

• Hit small, independent salons particularly hard

Many in the industry call the rollout “rushed” and “commercially damaging.”

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Why the U.S. Hasn’t Followed

In contrast, the FDA has not restricted TPO in nail products. American salons can still legally use TPO-containing gels, and no health warnings have been issued.

This difference isn’t unusual:

• The EU often bans ingredients based on suggestive evidence.

• The U.S. typically waits for large-scale human studies before acting.

Past examples include BHA, BHT, and azodicarbonamide, which are restricted in Europe but still legal in U.S. cosmetics and foods.

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Other Risks Linked to Gel Manicures

TPO isn’t the only concern. Experts warn of additional health risks with gel nails:

• UV/LED dryers: A 2023 Nature Communications study found repeated UV exposure can cause DNA damage and raise skin cancer risk. Dermatologists recommend protective gloves or sunscreen during curing.

• Nail damage: Buffing nails too thin weakens the protective barrier, leading to breakage, splitting, or infection.

• “Greenies” infection: Bacteria like Pseudomonas aeruginosa can grow under lifting gel, turning nails green or blue. Though usually not life-threatening, it can be dangerous for those with weak immune systems.

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What Consumers and Salons Can Do

In Europe: Salons must dispose of all TPO products immediately and switch to TPO-free alternatives.

In the U.S. and elsewhere, consumers can protect themselves by:

• Checking ingredient labels for TPO

• Asking salons about TPO-free options

• Using sunscreen or UV-blocking gloves during curing

• Allowing breaks between manicures to let nails recover

• Seeking medical care for discolored or infected nails

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The Future of Nail Safety

The EU ban has split opinions:

• Supporters call it a step toward safer cosmetics.

• Critics warn of economic disruption and lack of solid human data.

Advocacy groups are pressing U.S. regulators to align with Europe, arguing consumers shouldn’t be exposed to chemicals deemed unsafe elsewhere. Whether the FDA will follow remains uncertain.

For now, one thing is clear: as of September 1, 2025, TPO is out of fashion in Europe — marking the start of a new chapter in nail care safety.