What is TPO in Nail Products – and Why Did the EU Ban It?

The nail industry has been buzzing recently about the European Union’s decision to ban Triphenylphosphine Oxide (TPO) in UV gel polishes. For salon owners, nail technicians, and clients, this raises important questions: What exactly is TPO? Why was it banned? And is the science behind the ban as clear as it seems?

Let’s break it down.

What is TPO?

TPO, short for Triphenylphosphine Oxide, is a photoinitiator commonly used in UV-curable products, including some gel nail polishes.

Photoinitiators are ingredients that react when exposed to UV light, allowing the gel to cure (harden) quickly. TPO has been popular in the nail industry because it provides:

• Efficient curing under UV/LED lamps

• A smooth, glossy finish

• Good color stability

In short, TPO helped make UV gels long-lasting and professional-looking.

Why Did the EU Ban TPO?

In 2025, the EU placed restrictions on TPO in cosmetics under the REACH regulation due to concerns that it could pose potential health risks. Some studies suggested that TPO:

• May be a skin sensitizer, leading to allergic reactions in certain individuals

• Could be linked to possible toxicological effects with repeated exposure

Because of these concerns, regulators decided to err on the side of caution and remove it from the list of approved cosmetic ingredients.

Are the Studies Flawed?

While consumer safety should always be the top priority, some experts in the nail industry have pointed out limitations in the studies that influenced the EU’s decision:

1. High Concentration Testing – Many toxicology studies test chemicals at concentrations far higher than what is used in real-world cosmetic formulations. In practice, nail gels typically contain very small amounts of TPO.

2. Direct Skin Exposure Assumptions – In actual nail application, gel polish is applied to the nail plate (a hardened surface), not directly to the skin. Most studies do not account for this barrier, which greatly reduces potential absorption.

3. Incomplete Risk Assessment – Some argue that regulators considered the hazard of TPO without fully assessing the risk at cosmetic-use levels. Hazard means a substance can cause harm under certain conditions, while risk evaluates the likelihood of harm under real-life exposure.

4. The Study was for Ingestion of TPO – The official study was done on the ingestion of TPO by lab rats. Which when converted to the affects on humans translates to drinking gallons of TPO in order to cause severe health conditions. The study had nothing to do with the application of TPO containing substances on skin or nails.

What This Means for Salons and Consumers

For nail professionals in Europe, the ban means that only TPO-free UV gels can now be sold and used legally. Many brands will need to reformulate or withdraw their products from the EU market.

At Tuesday in Love, we are proud to say that our Halal UV Gel Polish is completely TPO-free, lab-tested, and compliant with EU regulations. This means our customers can enjoy a safe, high-quality, and worry-free manicure experience.

The ban on TPO highlights a bigger issue: the need for balanced, science-based regulation in cosmetics. While it’s crucial to protect consumers, it’s also important to evaluate whether the risks are realistic at actual use levels.

For now, salons and consumers can rest assured that there are safe, effective alternatives available. And brands like Tuesday in Love are committed to providing clean, inclusive, and compliant nail products for everyone.