What Is Dilinoleic Acid/Ethylenediamine Copolymer?
Dilinoleic Acid/Ethylenediamine Copolymer is a synthetic polymer created by linking dilinoleic acid, a fatty acid dimer usually sourced from plant oils like soybean or sunflower, with ethylenediamine, a small nitrogen-containing molecule. This pairing produces a flexible, film-forming material that behaves a bit like a lightweight glue when spread on skin or hair.
The ingredient appeared in cosmetic labs in the 1990s when formulators looked for more sustainable, plant-derived alternatives to petroleum-based resins. By using fatty acids from renewable oils, chemists could build a polymer that adds staying power without a heavy or greasy feel.
Manufacturing starts with the dimerization of linoleic acid, which joins two fatty acid chains into a larger molecule. This dimer reacts with ethylenediamine in a controlled condensation process that removes small amounts of water and links the two components into long, repeating chains. The finished copolymer is purified, dried and milled into a fine powder or delivered as a pre-diluted solution for easy blending.
You are most likely to meet Dilinoleic Acid/Ethylenediamine Copolymer in products that need a thin, flexible film or a bit of extra thickness: long-wear foundations, mascaras, eyebrow gels, sunscreens, transfer-resistant lipsticks, leave-in conditioners, lightweight moisturizers and sheet mask essences.
Dilinoleic Acid/Ethylenediamine Copolymer’s Cosmetic Benefits/Uses
This multitasking polymer brings several practical perks to modern beauty formulas:
- Binding: Acts like a gentle adhesive that holds powders, pigments and other ingredients together so the product applies smoothly and wears longer
- Film forming: Creates a breathable, flexible layer on skin or hair that locks in active ingredients, boosts water resistance and improves the durability of color cosmetics
- Viscosity controlling: Thickens watery formulas just enough to stop them from running while keeping the texture light and easy to spread
Who Can Use Dilinoleic Acid/Ethylenediamine Copolymer
This polymer is generally well tolerated by all skin types including dry, combination, oily and sensitive skin because it stays on the surface and does not disturb the skin’s natural balance. Extremely acne-prone users may prefer lighter formulas since any film former can add a touch of occlusion, though this specific ingredient is considered low risk for pore blockage.
It is suitable for vegans and vegetarians. The dilinoleic acid portion is usually sourced from plant oils and no animal-derived materials are used in the synthesis or processing steps.
Current safety assessments have not flagged any pregnancy or breastfeeding concerns. That said this is not medical advice and anyone who is pregnant or nursing should check with a doctor before starting a new cosmetic product just to be sure.
The ingredient does not increase photosensitivity, so it will not make skin more prone to sunburn. As with any routine it still pairs well with daily sunscreen for overall skin health.
Potential Side Effects/Adverse Reactions
Responses to topical Dilinoleic Acid/Ethylenediamine Copolymer differ from person to person. The effects listed below are only potential outcomes and are unlikely for most users when the product is properly formulated and applied.
- Mild skin irritation
- Allergic contact dermatitis in individuals sensitive to residual ethylenediamine
- Transient eye stinging if the product accidentally gets into the eyes
- Build-up on hair shafts leading to heaviness if used in very high amounts or not washed out regularly
If any unpleasant reaction occurs stop using the product and seek advice from a healthcare professional
Comedogenic Rating
Rating: 1/5
Dilinoleic Acid/Ethylenediamine Copolymer sits on the surface and forms a lightweight film rather than seeping into pores, which keeps the clogging potential low. It does contain fatty acid chains so there is a slight theoretical chance it could trap oil or debris if layered heavily with rich creams, hence the score of 1 instead of 0.
Bottom line: generally suitable for acne-prone or breakout-prone skin, especially when used in lightweight formulations.
No standard comedogenicity testing scale covers every possible formulation, so how the polymer behaves can also depend on the other ingredients in the product.
Summary
Dilinoleic Acid/Ethylenediamine Copolymer works as a binder, film former and mild thickener. Its fatty acid backbone lets it spread smoothly while the nitrogen-containing links help it dry into a flexible mesh that locks pigments in place, boosts water resistance and gives liquids a silkier body.
It is not one of the superstar buzzwords you see splashed across ads, yet formulators reach for it whenever they need long-wear performance without a heavy feel, so you will quietly find it in many mascaras, foundations and leave-in hair products.
Safety reviews conclude it has a very low risk of irritation or pore blockage for most users. Still, skin can be unpredictable so it is always wise to patch test any new product that contains this or any other unfamiliar ingredient.