What Is Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer?
Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer is a synthetic polymer made by reacting acetylenediurea, formaldehyde and tosylamide (also known as p-toluene sulfonamide). The result is a large, lattice-like molecule that forms a flexible film when it dries on the skin or nails. Chemists first explored this kind of polymer in the mid-20th century while searching for durable coatings. Its smooth finish and strong adhesive properties soon caught the attention of the cosmetic industry, which adopted it for nail lacquers in the 1970s. Today the ingredient is manufactured in controlled reactors where the three starting materials are mixed under heat and carefully balanced pH conditions. After polymerization, the mixture is purified and ground into a fine powder that disperses evenly in liquid formulas. You will most commonly spot it in nail polishes, topcoats, certain long-wear eyeliners and some peel-off face masks that rely on a thin, resilient film to lock ingredients in place.
Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer’s Cosmetic Benefits/Uses
This ingredient’s main role in a formula is as a film former. When the product dries the polymer sets into a clear, flexible layer that clings to the surface beneath it. In nail polish that layer boosts chip resistance, gloss and color payoff. In eyeliners it helps pigment stay sharp and smudge-proof. In peel-off masks it allows the mask to lift away in one piece, carrying debris and dead cells with it while leaving skin feeling smoother.
Who Can Use Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer
This polymer is considered non comedogenic and largely inert so it suits oily, combination and normal skin without causing clogging or extra shine. Dry or sensitive skin can also tolerate it since it does not draw out moisture, although very reactive skin may tingle if it already struggles with sulfonamide or formaldehyde based substances.
The material is produced entirely in the lab from petrochemical feedstocks and contains no animal derived components which makes it acceptable for vegans and vegetarians.
Topical use during pregnancy or while breastfeeding is not known to pose a risk because the molecule is too large to penetrate deeply and systemic exposure is negligible. This is not medical advice and anyone who is pregnant or nursing should clear all personal care products with a qualified physician just to be safe.
The polymer does not absorb UV light so it does not cause photosensitivity. It also plays nicely with most actives such as retinoids or acids since it simply forms a film rather than reacting with them.
Potential Side Effects/Adverse Reactions
Responses to topical Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer vary from one individual to another. The points below outline potential side effects that could occur, yet most users experience none of these issues when the ingredient is used correctly in a finished product.
- Mild skin redness or itching on sensitive skin
- Contact dermatitis in people allergic to sulfonamides or formaldehyde releasers
- Nail dryness or brittleness after frequent use of high concentration nail lacquers
- Eye irritation or watering if liquid eyeliner containing the polymer enters the eye before fully drying
- Respiratory irritation from inhaling solvent fumes during vigorous nail polish application in a poorly ventilated area
If any of these reactions appear stop using the product immediately and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 0/5. The molecule is far too large and inert to seep into pores or mix with skin oils so it cannot block follicles or trigger acne. Its role is simply to form a film on the very top surface of skin or nails. That makes it suitable for people who are prone to breakouts. Any congestion that might occur after using a product containing this polymer is more likely linked to other ingredients such as heavy oils, plasticizers or drying solvents that often accompany nail or eye formulas rather than the polymer itself.
Summary
Acetylenediurea/Formaldehyde/Tosylamide Crosspolymer is used for one main reason: it dries into a smooth flexible film that locks color on nails, stabilizes eyeliner and lets peel-off masks come off in a clean sheet. By interlinking its long chains as the product evaporates, it creates a tough yet bendy coating that resists chips, smudges and flaking.
The polymer is fairly popular in nail lacquers and long-wear eye makeup but you will rarely see it in everyday moisturizers or serums because those products do not need a hard film. It has built a good safety record over several decades with very low reports of irritation or allergy except in people already sensitive to sulfonamides or trace formaldehyde. Overall it is considered safe for topical use yet, as with any new cosmetic, it is smart to do a small patch test to rule out personal sensitivity before applying a full manicure or face treatment.