The phrase “formaldehyde-free” sounds reassuring.

And in one sense, it can be useful.

But in lash adhesive chemistry, it does not automatically answer every safety question about the finished product.

That distinction matters because an ingredient list tells us what was intentionally formulated into a product. It does not always tell us everything that may be formed, released, detected, or present under certain conditions during storage, application, or polymerization.

Ingredient List vs. Finished Product

When you read an ingredient list, you are looking at the substances intentionally incorporated into the formulation.

That is valuable information.

But formulation chemistry does not stop once ingredients are mixed together.

Cyanoacrylate-based lash adhesives are highly reactive systems. Their behaviour may be influenced by manufacturing conditions, storage, moisture, temperature, impurities, and polymerization during application.

Those are not the same question.

A product may therefore be accurately described as formaldehyde-free in terms of intentionally added ingredients, while analytical testing may still identify formaldehyde release from the finished adhesive.

That does not automatically mean the label is fraudulent, and it does not mean every adhesive presents the same exposure profile.

It means the chemistry is more nuanced than one marketing phrase.

What Did the 2026 Danish Government Study Find?

In 2026, the Danish Environmental Protection Agency published a survey and risk assessment examining beauty adhesives, including products used around the eyes.

The project assessed beauty adhesive formulations, chemical composition, consumer use, and potential health concerns.

Among the findings, investigators reported that some tested beauty adhesives, including eyelash adhesives, released measurable formaldehyde.

The study also evaluated other potential concerns associated with beauty adhesives, including acrylates, irritation, sensitization, and product pH.

Does This Mean Lash Adhesive Is Unsafe?

No. That would be an overly broad conclusion.

Safety depends on multiple variables, including:

• the specific adhesive formulation
• the amount of any substance released
• exposure concentration
• frequency and duration of exposure
• ventilation
• application technique
• proximity to the eye and skin
• individual susceptibility or sensitization

A chemical can be detectable without necessarily being present at a level that creates meaningful risk.

That is why toxicological assessment requires more information than simply asking whether a substance is present.

Why Cyanoacrylate Chemistry Matters

Professional eyelash extension adhesives commonly rely on cyanoacrylate monomers.

In Canada, Health Canada specifically restricts the use and sale of several cyanoacrylate-based adhesives used for eyelash extensions, including ethyl cyanoacrylate, methyl cyanoacrylate, and isopropyl cyanoacrylate.

These products must be sold for professional use only and must carry specific caution statements, including directions that the eye be protected and immobilized during application.

Cyanoacrylates polymerize rapidly in the presence of moisture. That reactivity is exactly what makes them useful for professional lash extensions — but it is also why the finished adhesive system should be evaluated as more than a simple list of raw ingredients.

“Formaldehyde-Free” Is Not the Same as “Risk-Free”

A formaldehyde-free claim generally speaks to one specific substance.

It does not automatically tell us:

• whether the product contains other sensitizers
• whether trace impurities may be present
• whether degradation products may form
• whether volatile compounds may be released
• whether the finished product has undergone analytical testing
• whether the product has been evaluated for irritation
• whether the adhesive complies with professional-use requirements

So while “formaldehyde-free” can be meaningful information, it should not be treated as shorthand for:

Those are entirely different claims.

What Does Health Canada Say About Lash Adhesives?

Health Canada places specific conditions on cyanoacrylate-based eyelash extension adhesives.

These products must be sold for professional use only, and labels must include required cautionary language and instructions relating to trained professional application and eye protection.

Health Canada also conducted a targeted 2023–2024 compliance verification project involving 87 cyanoacrylate-based eyelash extension adhesive products.

Identified issues included:

• missing required warning statements
• products not meeting professional-use-only conditions
• notification issues
• retail distribution concerns

Corrective actions included stop-sale and stop-distribution measures.

Health Canada specifically notes that the products were targeted for inspection based on likelihood of non-compliance, so the results should not be treated as representative of the entire market.

What Should Lash Professionals Actually Look For?

Rather than relying on one marketing claim, evaluate the adhesive as a complete system.

The Bigger Lesson for the Lash Industry

The lash industry often evaluates products using simple labels:

formaldehyde-free • latex-free • hypoallergenic • sensitive • low-fume • non-toxic

But cosmetic and adhesive chemistry rarely fits neatly into a single marketing phrase.

A better question is:

An ingredient list tells us what was formulated.

Analytical testing can help tell us what may be detected or released from the finished product.

Toxicology then asks whether the resulting exposure is meaningful.

Those are three different layers of evaluation.

References

1. Danish Environmental Protection Agency. Survey and Risk Assessment of Beauty Product Adhesives. 2026.
   View source
2. Health Canada. Cosmetic Ingredient Hotlist — Cyanoacrylate-Based Adhesives.
   View source
3. Health Canada. Compliance Verification Project 2023–2024: Cosmetic Regulations — Cyanoacrylate Ingredients.
   View source