What Is Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer?
Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer is a synthetic polymer created by linking acrylic acid units with acrylamidomethyl propane sulfonic acid units. The resulting chain has both carboxylic and sulfonic groups, giving it the ability to grab on to metal ions and swell in water. First introduced in the late 1980s as part of a new wave of multifunctional acrylic copolymers, it quickly found a place in cosmetics thanks to its stability and versatility.
Manufacturing usually starts with purified acrylic acid and acrylamidomethyl propane sulfonic acid. These monomers are mixed in water, then a gentle, heat-controlled free-radical reaction links them together into long chains. Once polymerized, the gel-like mass is neutralized, filtered and dried or left as an aqueous solution depending on the intended use.
You will most often spot this copolymer in gels, lotions, sheet mask serums, anti-aging creams, styling gels, micellar cleansers and sunscreens. Formulators value it for keeping textures smooth, preventing ingredient separation and helping actives stay effective over time.
Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer’s Cosmetic Benefits/Uses
This ingredient pulls double duty in a formula, giving chemists two practical benefits they can rely on.
- Chelating: It binds to trace metal ions that sneak into a product through water or raw materials. By locking these metals up it stops them from breaking down delicate ingredients such as fragrances or colorants which helps extend shelf life and keeps textures and scents consistent
- Viscosity Controlling: The polymer swells when hydrated, thickening the formula and creating a smooth cushiony feel. This lets brands offer gels that stay in place on the skin, lotions that spread evenly and cleansers that feel rich without relying on heavy oils
Who Can Use Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer
This polymer is considered gentle and noncomedogenic so it fits well with most skin types including oily, dry, combination and sensitive. Because it largely stays on the skin’s surface and does not deliver active chemical action it rarely triggers issues even for reactive complexions. There are no known concerns that make it unsuitable for any specific skin type, though anyone with a history of acrylic allergies should be cautious.
The ingredient is fully synthetic and contains no animal derived raw materials so it is suitable for both vegetarians and vegans.
No research points to problems for pregnant or breastfeeding women when this copolymer is used topically in cosmetic amounts. Still this text is not medical advice and anyone who is pregnant or nursing should have their doctor review any skincare product they plan to use.
The polymer does not absorb UV light or make skin more sensitive to the sun so it is not considered photosensitising.
Potential Side Effects/Adverse Reactions
Responses to topical Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer differ from person to person. The effects below are only potential issues and are unlikely for the average user when the ingredient is correctly formulated.
- Mild skin irritation such as redness or itching
- Allergic contact dermatitis in individuals already sensitised to acrylic compounds
- Eye stinging if a high concentration product accidentally gets into the eyes
- Very rare clogging or heaviness when used in extremely thick gels on acne-prone skin
If any discomfort or unusual reaction occurs discontinue use and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0/5
This copolymer is a large water-holding molecule that sits on the surface and does not penetrate pores or leave an oily residue, so it has virtually no potential to clog follicles. Its main job is to thicken water-based formulas and bind metal ions, which keeps it chemically inactive toward sebum. For this reason it is generally considered safe for people who are prone to acne or breakouts.
As with any ingredient, the finished product matters. Extremely heavy gels packed with occlusive oils can still feel suffocating even if the copolymer itself is noncomedogenic, so always judge the full formula rather than the single component.
Summary
Acrylic Acid/Acrylamidomethyl Propane Sulfonic Acid Copolymer thickens watery mixtures into smooth gels and grabs stray metal ions that could spoil a formula. It performs these roles by swelling in water, which boosts viscosity, and by using its carboxylic and sulfonic groups to lock on to metals, keeping sensitive ingredients stable.
It is not the flashiest name on an ingredient list but it pops up in plenty of mainstream gels, lotions, sunscreens and micellar cleansers because it is reliable, cost effective and easy to formulate with.
Current safety data shows a very low risk of irritation or comedogenicity, making it suitable for nearly all skin types. That said, skin is personal so it is always smart to patch test any new product that contains this or any other unfamiliar ingredient.