Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 27, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer?

Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer is a man-made polymer created by linking together two building blocks: dimethylacrylamide and ethyltrimonium chloride methacrylate. The first gives flexibility while the second carries a gentle positive charge, allowing the finished material to interact well with hair and skin surfaces. Chemists introduced this copolymer in the late 1990s when brands started to look for lightweight thickeners that could also leave a smooth feel. Production begins with water, the two monomers and a small amount of initiator. Under heat the monomers bond into long chains, then the mixture is purified, dried and milled into a fine powder or kept as a clear liquid concentrate.

In cosmetics the ingredient appears in leave-in and rinse-off hair treatments, conditioners, styling gels, facial serums, sheet masks, lightweight lotions, sunscreens and makeup primers. Formulators choose it when they want a silky finish without heavy waxes or oils.

Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer’s Cosmetic Benefits/Uses

This copolymer is valued mainly for its role as a viscosity controller. By thickening water-based formulas it helps create a pleasant texture that spreads easily and stays put on skin or hair. Stable, clear and effective at low levels, it lets brands reduce gum content, improves suspension of pigments or actives and cuts down on formula separation, leading to a smoother user experience.

Who Can Use Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer

This polymer is considered gentle and works well for most skin types including oily, dry, combination and mature skin. Because it is lightweight and free from pore clogging oils it rarely causes breakouts, making it a reasonable choice for acne-prone users. Those with extremely reactive or allergy-prone skin should still keep an eye on the ingredient list since any synthetic polymer can occasionally trigger sensitivity, but such cases are uncommon.

The material is completely synthetic and does not rely on any animal-derived substances during manufacture, so it is generally seen as suitable for both vegans and vegetarians. As always people following a strict cruelty-free lifestyle may wish to confirm the finished product’s animal testing policy with the brand.

Current safety data shows no evidence that the ingredient is absorbed through intact skin in meaningful amounts, so it is not expected to pose a risk during pregnancy or while breastfeeding. This is not medical advice and anyone who is pregnant or nursing should run their skincare choices past a qualified doctor to be on the safe side.

Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer does not make skin more sensitive to the sun and has no known effect on photosensitivity. It is also odorless, colorless and compatible with most other cosmetic ingredients, which keeps the chance of cross-reactions low.

Potential Side Effects/Adverse Reactions

Responses to topical Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer can vary from person to person. The points below outline potential side effects but they are unlikely for the average user when the ingredient is used correctly in a finished product.

  • Mild skin irritation such as transient redness or itching, usually in people with very sensitive skin
  • Contact dermatitis in rare cases where the immune system reacts to the polymer or to other formula components
  • Eye irritation if a product containing the polymer accidentally gets into the eyes
  • Allergic reaction presenting as swelling or hives, uncommon but possible in individuals with multiple chemical sensitivities

If any of these effects occur stop using the product and seek advice from a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 0/5

Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer is water soluble and oil free so it does not sit in pores or create the kind of oily film that can lead to clogged follicles. It simply thickens the water phase then rinses or wears off without leaving a residue that bacteria can feed on. For that reason formulators regard it as non comedogenic.

Suitable for acne prone and breakout prone skin.

Because it is charged and stays mostly on the surface it is unlikely to interact with sebum or other pore lining material which keeps the risk of congestion low.

Summary

Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer is used to control viscosity giving lotions gels and sprays a smooth glide and helping pigments or actives stay evenly suspended. Its lightly charged structure lets it coat hair or skin with a silky feel without adding weight or greasiness.

It is not the most famous ingredient on labels but it shows up quietly in many modern formulas where brands want clarity and light texture instead of the stickiness gums can bring.

Current data shows it is generally safe for all skin types with a very low risk of irritation or clogged pores. Still skin can be unpredictable so try a small patch first when testing any new product that contains it.

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