What Is Diethylene Glycol/Dimer Dilinoleic Acid Copolymer?
Diethylene Glycol/Dimer Dilinoleic Acid Copolymer is a man-made ingredient created by linking diethylene glycol, a small water-loving molecule, with dimerized dilinoleic acid, a fatty acid derived mainly from plant oils such as soybean or sunflower. The result is a flexible copolymer that combines the light feel of glycols with the softening nature of long-chain fatty acids.
Chemists first explored this type of copolymer in the late twentieth century while searching for film formers that felt less sticky than traditional resins yet offered better moisture resistance. Over time formulators realized it not only formed smooth films but also protected shades and added slip, so it found a place in color cosmetics, hair sprays, sunscreens and leave-on skin care.
The manufacturing process starts with the controlled reaction of plant-sourced linoleic acid to form a dimer. This dimer is then reacted with diethylene glycol under heat and a catalyst to create long repeating units. The finished copolymer is purified, cooled and supplied as a viscous liquid or soft resin that blends easily with oils and silicones.
You are most likely to encounter Diethylene Glycol/Dimer Dilinoleic Acid Copolymer in long-wear foundations, liquid lipsticks, waterproof mascaras, styling sprays, anti-frizz serums, moisturizers aiming for a light after-feel and sunscreens designed to stay put when exposed to water or sweat.
Diethylene Glycol/Dimer Dilinoleic Acid Copolymer’s Cosmetic Benefits/Uses
This versatile copolymer delivers several useful effects in beauty formulas
- Film forming: Creates a thin flexible layer that locks pigments in place, boosts water resistance and helps actives stay on the skin or hair longer
- Hair conditioning: Smooths the hair shaft, reduces static and adds a soft touch without heaviness making styles look sleeker and last longer
- Light stabilizer: Helps protect colorants and other sensitive ingredients from breaking down when exposed to UV light so products keep their shade and performance
- Skin conditioning: Adds a subtle emollient feel that leaves skin feeling soft and non-greasy while helping reduce moisture loss
Who Can Use Diethylene Glycol/Dimer Dilinoleic Acid Copolymer
This lightweight copolymer is considered friendly for most skin types. Dry and normal skin benefit from its soft conditioning feel while oily and combination skin appreciate that it is not heavy or greasy. Sensitive skin generally tolerates it well because the molecule is large and non-penetrating, though anyone with a history of allergies to synthetic polymers should stay alert to possible irritation.
The ingredient is synthesized from diethylene glycol and plant-derived fatty acids, with no animal inputs, so products that rely on it are typically suitable for vegans and vegetarians. Always check the full ingredient list since companion ingredients may not share the same status.
Current safety data show no specific hazards for pregnant or breastfeeding women when the ingredient is used topically in cosmetics. This is not medical advice. Expectant or nursing mothers should have any skincare routine reviewed by their healthcare professional to be sure it fits their individual situation.
Diethylene Glycol/Dimer Dilinoleic Acid Copolymer does not make skin more sensitive to sunlight and will not interfere with sunscreen filters. It is also odorless and colorless so it rarely affects fragrance or dye allergens in a formula.
Potential Side Effects/Adverse Reactions
Reactions to topical Diethylene Glycol/Dimer Dilinoleic Acid Copolymer vary from person to person. The effects listed below are only potential outcomes and are unlikely for the average user when the ingredient is used at normal cosmetic levels.
- Transient skin redness or mild stinging in very sensitive individuals
- Contact dermatitis in those already allergic to glycol-based polymers
- Scalp buildup or dullness if overused in heavy styling products
- Eye irritation if mascara or spray accidentally gets into the eyes
If you experience any of the above issues stop using the product and consult a qualified healthcare provider or dermatologist.
Comedogenic Rating
Rating: 1 / 5
This copolymer is a large, branched molecule that tends to sit on the surface rather than work its way into pores. It delivers a light, non-greasy finish and is typically used at low levels, so it is very unlikely to trap oil or dead skin cells.
Because of its low rating it is generally suitable for people who are prone to acne or breakouts.
Keep in mind that every formula is different. If the product also contains heavier oils or waxes the overall pore-clogging potential could rise even with this low-risk polymer present.
Summary
Diethylene Glycol/Dimer Dilinoleic Acid Copolymer forms flexible films, conditions hair, shields colors from light and adds a soft feel to skin. It does this by combining a water-friendly glycol with a plant-derived fatty acid, creating a resin that coats surfaces evenly then dries without stickiness.
While not a headline ingredient like hyaluronic acid or retinol, it shows up quietly in long-wear makeup, sunscreens and styling sprays where staying power matters. Formulators like it because it works in both water-based and oil-based systems and plays nicely with silicones.
Current data show it to be safe for topical use with a very low irritation and comedogenic profile. As with any new product it is wise to do a small patch test to make sure your skin agrees.