What Is C18-22 Alkyl Peg-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer?
C18-22 Alkyl PEG-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer is a man-made polymer created by linking two kinds of building blocks: a fatty alcohol-based methacrylate that carries 18 to 22 carbon atoms and a diethylaminoethyl methacrylate that lends a light, water-friendly quality. The result is a large flexible molecule that can sit at the border of oil and water, making it a useful helper in many skin and hair formulas.
The ingredient was first explored in the late 1990s when chemists looked for gentler alternatives to traditional detergents and thickeners. By attaching polyethylene glycol (PEG) chains to long-chain fatty alcohols they were able to craft a polymer that could tame oily phases yet rinse away without leaving a heavy film. Over time its multitasking nature—keeping mixtures stable while adding a silky feel—earned it a spot in modern cosmetic labs.
Production starts with plant-derived fatty alcohols, often sourced from coconut or rapeseed oil. These are reacted with ethylene oxide to form PEG-25 chains, then combined with methacrylic acid to create the alkyl methacrylate monomer. Separately, diethylaminoethyl methacrylate is prepared from ethanol and dimethylaminoethyl methacrylate. Both monomers are then polymerized in a controlled environment to yield the final copolymer, which is purified and dried into a fine powder or delivered as a concentrated liquid.
You will most often find this ingredient in lightweight lotions, facial cleansers, micellar waters, sunscreens, leave-on hair conditioners, styling creams, sheet mask essences and BB or CC creams where it acts behind the scenes to keep the texture smooth and stable.
C18-22 Alkyl Peg-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer’s Cosmetic Benefits/Uses
This multitasking polymer brings several formulating perks:
- Emulsion stabilising: It positions itself between oil droplets and the surrounding water phase, preventing separation so creams and lotions stay uniform from the first pump to the last drop.
- Cleansing: Its mild surfactant properties help lift dirt, makeup and excess oil without stripping skin or hair, making it ideal for gentle face washes and micellar formulas.
- Viscosity controlling: By thickening watery solutions just enough it gives products a pleasing glide and body, improving spreadability while reducing the need for heavier gums or waxes.
Who Can Use C18-22 Alkyl Peg-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer
This ingredient is generally well tolerated by all skin types. Its lightweight, non greasy feel suits oily and combination skin while its ability to hold water in place helps relieve surface dryness for normal and dry complexions. Sensitive skin usually handles it well because it is free of harsh detergents, though anyone with a history of acrylic resin allergies should proceed with caution.
The fatty alcohol portion is sourced from plants and the rest of the molecule is produced synthetically so it is suitable for vegetarians and vegans as long as the finished formula has not been blended with animal derived additives.
No data suggests a risk for pregnancy or breastfeeding when used topically. The molecule is too large to penetrate deeply and it is not known to interfere with hormonal pathways. This is not medical advice; expectant or nursing mothers should still have their doctor review any product containing the ingredient to be certain it fits their personal circumstances.
C18-22 Alkyl PEG-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer does not increase photosensitivity and can be used in both daytime and nighttime formulas. It also plays well with most commonly used actives including acids, retinoids and antioxidants, making it a flexible option in layered routines.
Potential Side Effects/Adverse Reactions
Responses to topical C18-22 Alkyl PEG-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer can vary from person to person. The following list covers potential issues only. When formulated correctly most users experience none of these effects.
- Mild transient irritation such as slight redness or stinging on very sensitive or broken skin
- Rare contact allergy presenting as itching rash or swelling in individuals allergic to acrylic resins
- Build up on fine hair which can leave strands feeling coated if the product is not rinsed thoroughly
- Eye discomfort if a concentrated formula accidentally enters the eyes during cleansing
If any negative reaction occurs stop using the product and consult a healthcare professional or dermatologist for guidance.
Comedogenic Rating
Rating: 1 / 5
This copolymer is a bulky water-soluble molecule that does not easily settle into pores. Although part of its structure is derived from long-chain fatty alcohols, those chains are locked into the polymer and are unable to act like free oils. Most lab and in-use data show little to no pore-clogging potential which is why it earns a very low score of 1.
Because of that low rating the ingredient is generally considered suitable for people who are prone to acne or breakouts.
As with any film-forming agent, overuse in leave-on products could contribute to buildup if cleansing is inadequate but this is uncommon at typical usage levels.
Summary
C18-22 Alkyl PEG-25 Methacrylate/Diethylaminoethyl Methacrylate Copolymer works as an emulsion stabiliser, a mild cleanser and a light viscosity controller. It anchors itself at the boundary between oil and water to keep formulas mixed, its gentle surfactant pockets lift away dirt and excess sebum and its long polymer chain adds body so liquids feel silky instead of runny.
The ingredient is more popular in the lab than on ingredient-watch lists. Formulators appreciate its multitasking nature but its long scientific name keeps it under the radar for most shoppers.
Safety profiles rate it as low risk for irritation, sensitisation and comedogenicity when used as directed. Still, skin is personal so it is wise to patch test any new product that contains this copolymer before full use.