TPO is not the same as TPO-L

Prohibited ingredients :

Trimethylbenzoyl Diphenylphosphine Oxide

Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide

(2,4,6-trimethylbenzoyl)diphenylphosphine oxide

2,4,6-Trimethylbenzoyldiphenylphosphine oxide

Permitted ingredients :

Ethyl Trimethylbenzoyl Phenylphosphinate

Ethyl phenyl (2,4,6-trimethylbenzoyl)phosphinate

Ethyl (2,4,6-trimethylbenzoyl)phosphinate

TPO-L - Ethyltrimethylbenzoylphenylphosphinate (CAS: 84434-11-7)

TMO (TPO-R) - Trimethylbenzoylditolylphosphine oxide / Di-p-tolyl (2,4,6-trimethylbenzoyl) phosphine oxide (CAS: 270586-78-2)

BAPO - Bis-trimethylbenzoylphenylphosphine oxide (CAS: 162881-26-7)

Hydroxycyclohexylphenyl ketone - (CAS: 947-19-3)

Introduction

Photoinitiators play a central role in light-curing nail products. They ensure that gels and polishes cure reliably under UV or LED light. One of the best-known examples is TPO . However, not all TPOs are created equal. The abbreviation encompasses various chemical substances with their own properties, names, and regulatory statuses. It is therefore important for the industry and users to understand the current situation – especially since the EU will be implementing new regulations from September 2025.

What exactly is TPO?

TPO stands for trimethylbenzoylphenylphosphine oxide – a compound that absorbs light energy and breaks down into radicals. These initiate polymerization , the curing process of gels.

However, several variants of TPO exist, which differ chemically. The two most important are TPO-G and TPO-L .

Chemical differences

TPO-G (classic)

Chemical name: Trimethylbenzoyl diphenylphosphine oxide
CAS No.: 75980-60-8
Properties: hardens quickly and reliably, but increases the risk of skin sensitization.
Regulatory situation: Due to a new EU regulation , no longer permitted in cosmetic products from September 2025.

TPO-L (Alternative)

Chemical name: Ethyl Trimethylbenzoyl Phenylphosphinate
CAS No.: 84434-11-7
Properties: better tolerability, lower allergy potential, same function as a photoinitiator
Regulatory situation: remains permissible under current EU legislation

Legal classification: TPO-G vs. TPO-L

A recent expert dialogue clarifies:

"Basically, there are two substances: TPO-G and TPO-L . From September 1, 2025, only TPO-G will be banned – TPO-L will remain permitted."

Here's an overview of the details:

TPO-G
- CAS No.: 75980-60-8 | EC No.: 278-355-8
- No longer permitted in the EU from September 2025
- Affected by the 21st ATP to the CLP Regulation
TPO-L
- CAS No.: 84434-11-7 | EC No.: 282-810-6
- It remains permitted .
- Not affected by the reclassification

👉 This makes it clear: The EU regulation forces the industry to withdraw from TPO-G.

Why was TPO-G banned?

1. Classified as toxic to reproduction (CMR 1B)

The EU has classified TPO-G as CMR category 1B under the 21st ATP to the CLP Regulation – meaning it is considered a substance with potential reproductive toxicity. This classification is based on scientific assessments and includes potential risks to reproduction.

2. Automatic exclusion under EU cosmetics regulation

According to the Cosmetics Regulation (EC) No. 1223/2009 , CMR substances of categories 1A or 1B may not be used in cosmetic products. This resulted in a ban on TPO-G coming into effect on 1 September 2025.

3. Precautionary principle in consumer protection

The EU is considered a pioneer in consumer protection – even though no immediate dangers from the use of TPO-G were known, its classification as CMR 1B was deemed a sufficient risk to prohibit this ingredient as a precautionary measure . Regulation prioritizes security over uncertainty.

Conclusion: What does this mean for nail products?

The upcoming ban on TPO-G does not mean that manufacturers or nail salons have put unsafe or defective products on the market in the past.

All previously used formulations containing TPO-G complied with applicable legal requirements and were evaluated and approved according to the scientific knowledge valid at the time. The new classification under the CLP Regulation now changes the legal basis – not the actual properties or safety of the previously used products.

Not all TPO is the same. The abbreviation refers to different substances.
Due to the EU reclassification, TPO-G may no longer be used from September 2025 .
TPO-L remains permitted.

Our promise as a manufacturer

As one of the major suppliers and manufacturers in the field of nail design, we have gradually switched our products to a TPO-free formulation – without compromising on durability, color intensity and performance.

With emmi®NAIL, you're on the safe side: from September 1, 2025, all products will contain TPO-L-free formulations . This guarantees you the highest quality and safety for the future with all emmi®NAIL products.

Discover UV gel for professional nail salons now.