Eyelash serums: what the European opinion really says about prostaglandins

On February 2, the European Scientific Committee on Consumer Safety assessed three prostaglandin analogues used in eyelash serums. It could not declare a single one of them safe. This is not a ban, and that is precisely the part no one is explaining.

The distinction is not a technicality: the committee did not demonstrate that these serums cause cancer or reproductive harm. It said something different and equally serious: the data presented by the companies are not sufficient to demonstrate that they are safe. Between “it has not been proven harmful” and “it has been proven safe” lies the entire space in which these products are selling.

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A story that begins in ophthalmology

The association between prostaglandins and eyelash growth did not originate in a cosmetic company’s laboratory. It arose from an effect observed during the use of eye drops developed to lower pressure inside the eye in the treatment of glaucoma.

Among the changes reported by people undergoing those therapies were longer, thicker, more numerous, and darker lashes. What had been a side effect eventually became the desired result: in 2008, the U.S. Food and Drug Administration approved 0.03% bimatoprost as a medicine for eyelash hypotrichosis.

This origin matters for two opposite reasons, and both must be kept in mind.

The first is that the effect on growth is neither subjective perception nor the photographer’s achievement: in the case of bimatoprost, it is supported by pharmacological activity and studies conducted to register a medicine.

The second is that none of this automatically applies to a cosmetic serum. The analogues assessed in Europe are different molecules, at different concentrations, supported by different dossiers. Saying “prostaglandins” as if they were all the same thing is imprecise; but treating them as ordinary beauty ingredients with no biological activity is much more so.

Why these serums have become so popular

There are four reasons, and they are all understandable.

The result is visible. The lash area lends itself to photographic comparisons like few others. A change in length shows in a second; the gradual improvement of a skin barrier does not.

The gesture is simple. Applying it along the lash line in the evening seems less demanding than a professional treatment, and simplicity encourages consistency.

The language is ambiguous. “Eyelash serum,” “lash enhancer,” and “conditioning treatment” sound like variations of the same thing. They do not indicate whether the formula merely conditions the hair shaft or contains a substance capable of interfering with the hair growth cycle.

The boundary between cosmetic and pharmacological is not intuitive. If a product is sold as a cosmetic, it is generally assumed to act on the surface and pose a modest risk. It is precisely this simplification that the European opinion calls into question: a substance can be included in a cosmetic and have potent pharmacological activity even at extremely low doses.

What the European committee concluded

On February 2, 2026, the Scientific Committee on Consumer Safety, the independent committee that assesses the risks of cosmetic ingredients for the European Commission, adopted its final opinion, SCCS/1680/25, on prostaglandin analogues intended for eyelash and eyebrow products. It was published on February 10.

The dossier concerned three substances proposed at very low concentrations:

• Ethyl Tafluprostamide, up to 0.018%;
• Methylamido-Dihydro-Noralfaprostal, up to 0.03%;
• Isopropyl Cloprostenate, up to 0.005%.

Pay attention to the names, because anyone searching for the document may not find them. The same three molecules appear under two different nomenclatures: Ethyl Tafluprostamide is Dechloro Dihydroxy Difluoro Ethylcloprostenolamide, abbreviated DDDE, and Methylamido-Dihydro-Noralfaprostal is also referred to as Norbimatoprost. It is a technical detail that becomes a practical problem: the name you read on the label and the name under which the substance was assessed may not match.

The conclusion is clear: based on the information presented, none of the three can be considered safe for use in cosmetics intended to promote eyelash and eyebrow growth.

The reason is not a general distrust of “powerful” ingredients. The committee identifies two specific issues: the potent pharmacological activity of these substances even at low concentrations, and the lack of sufficient data to rule out reproductive and developmental toxicity effects. On this second point, it adds a significant observation: a substantial proportion of people who use these products are of childbearing age.

There is also a distinction that needs to be reported in full, because it always disappears from the headlines. The available data have not shown genotoxic potential for the three substances, so no concern about genotoxic carcinogenicity was raised. However, in the absence of adequate carcinogenicity studies, the committee states that it cannot rule out non-genotoxic carcinogenicity. This is not the same as saying “causes cancer.” It means “we do not have the tools to rule it out.”

A scientific opinion is not a ban

This step needs to be understood properly, and it is the first thing to get lost when the news reaches social media.

The committee conducts the scientific risk assessment. Regulatory decisions, namely any amendments to the annexes of the Cosmetics Regulation, are the responsibility of the European Commission, which manages the risk in a subsequent and separate step.

So the opinion of February 2 is not, by itself, an already operative ban on every serum on the market. It is, however, a very strong regulatory signal: after reviewing the submitted dossiers, the European scientific authority did not find a concentration it could declare safe for the proposed cosmetic use.

“In medicine, these risks are accepted because the treatment is necessary and the patient is informed. A cosmetic serves no necessary purpose and informs no one.”

France already has a documented case

While Europe was assessing the dossiers, a national agency recorded a concrete case, and that is the part that struck me most.

In February 2025, the French health safety agency was alerted through its cosmetovigilance system by a report from a young woman: after five months of daily application at the base of the upper eyelashes, her left eye had become noticeably darker, and there was fat loss around both eyes that accentuated her dark circles. Analysis of the product confirmed the presence of isopropyl cloprostenate.

The December 2025 cosmetovigilance bulletin notes that these effects are known in glaucoma therapy — irreversible darkening of the iris, chronic irritation, and periorbital fat atrophy, which affects almost 10% of patients treated with those eye drops.

And here comes the reasoning that, in my opinion, is the key to the whole matter. In medicine, those risks are considered acceptable for two reasons: the treatment is essential, and the patient is informed by the doctor and the package leaflet. For a cosmetic sold to make eyelashes longer, neither the first nor the second reason applies. There is no therapeutic need to justify the risk, and those effects are not mentioned anywhere on the packaging.

What has been demonstrated, what is plausible, and what remains to be verified

Let me try to put things in order, because this topic involves enormous confusion between the three levels.

Demonstrated

• As a medicine, bimatoprost increases eyelash growth, thickness, and pigmentation.
• Prostaglandins and their analogues have biological activity in the ocular and periocular areas.
• The European committee could not consider the three analogues assessed safe at the proposed concentrations, based on the data received.
• There is at least one case documented by a national authority involving iris darkening and periorbital fat loss after cosmetic use.

Plausible, but not automatically transferable

• The effects observed with ophthalmic medicines used in the same area are useful signals when assessing cosmetic analogues as well, but the molecule, dose, vehicle, and method of application change the picture.
• A product that shows very noticeable growth could contain a biologically active substance. The photographic result alone does not make it possible to identify it.

Still to be verified

• The real risk profile of each individual serum in everyday use.
• The frequency of adverse effects for the different analogues, at the concentrations actually used.
• The long-term safety of substances for which adequate data are lacking.
• The effectiveness of “prostaglandin-free” serums: this wording excludes one category; it does not prove that the product makes lashes grow. It works the same way as the “free from” wording I wrote about in relation to sunscreens.

How to read a lash serum without being guided by the claim

The first step is to separate three questions that are always confused.

1. Does the product make the lashes softer, shinier, and less prone to breakage?
2. Is there data on the finished formula showing a measurable increase in growth?
3. Does it contain a substance with pharmacological activity or an analogue of one?

A claim such as “fuller-looking lashes” may simply result from a conditioning effect or less breakage. It does not amount to a change in the growth cycle, and it should not suggest one.

Then read the full INCI list, looking for the complete names rather than just familiar words. Isopropyl Cloprostenate, Methylamido-Dihydro-Noralfaprostal, Ethyl Tafluprostamide: these names are long and not very intuitive, and their length does not in itself indicate danger. However, identifying the ingredient is essential, as it is the first right of anyone who buys a product.

If irritation, persistent redness, changes in pigmentation, or changes in the area around the eye appear, the prudent choice is to stop using it and consult a doctor. Anyone using medication for glaucoma or other eye conditions should not apply anything on top of it without medical advice.

My perspective as a formulator

This story interests me because it clearly shows how limiting it is to judge a cosmetic by its visible result.

When I see a striking before-and-after, my first question is not “does it work?” It is: through what mechanism, with what data, and with what safety margin. In my work, I look at the complete formula, the concentration, the area of application, the frequency of use, and the quality of the evidence. Around the eyes, where the skin is the thinnest on the face, this approach matters twice as much.

And I do not consider personal experience to be proof. Trying a product says something about texture, comfort, and practicality; it cannot rule out rare effects, long-term consequences, or reproductive issues. In cases like this, regulatory data must carry more weight than individual impressions, and far more than a viral video.

In conclusion

Eyelash serums are not all the same. Some act as conditioning treatments, others support the appearance of the eyelashes with cosmetic actives, while still others contain prostaglandin analogues with activity bordering on the pharmaceutical realm.

The European opinion does not authorize us to say that every eyelash serum is dangerous, nor that every alternative is automatically effective and safe. It says something more useful: for three specific analogues, the data provided were insufficient to demonstrate the safety of the proposed cosmetic use, and pharmacological activity at such low doses requires particularly rigorous assessment.

For anyone who buys the lesson is simple, and goes well beyond eyelashes: don't stop at the before and after. Growth may be a desirable result. But when a cosmetic visibly alters a biological process, it is always worth asking not only whether it works, but how, and based on what evidence.