What Is Polyester-36?
Polyester-36 is a man-made polymer created by linking together specific small molecules, including 5-isobenzofurancarboxylic acid, dimethylpropanediol, isobenzofurandione and propanediol. Through a controlled heating process called condensation polymerization, these building blocks join to form long, flexible chains that behave much like a very thin plastic film once they dry on the skin. The raw materials are typically sourced from petrochemical feedstocks, though the diols used can also be produced from plant-derived sugars, giving manufacturers some flexibility when choosing their supply chain.
Polyester technology entered the cosmetic world in the late 1980s as brands sought ingredients that could lock pigments in place without feeling stiff. Over time formulators refined the chemistry, arriving at Polyester-36 for its balanced mix of durability and comfort. Today it is produced in large reactors under strict temperature control, then purified and milled into a fine powder or viscous liquid that blends easily with oils, waxes and water-based phases.
Because it forms a breathable yet water-resistant layer, Polyester-36 shows up in long-wear makeup such as liquid foundations, eyeliners, mascaras and lip colors. It is also common in spray or lotion sunscreens, smoothing primers, peel-off face masks and hair styling products where a flexible hold is desired.
Polyester-36’s Cosmetic Benefits/Uses
This ingredient is valued for one main role within beauty formulas.
Film forming: When the product dries Polyester-36 creates a thin, invisible film that clings to skin or hair. This film helps pigments stay put, resists smudging brought on by sweat or oil and adds a soft, smooth feel. In sunscreens it boosts water resistance, while in hair products it provides light hold without crunch.
Who Can Use Polyester-36
Polyester-36 is generally well tolerated by most skin types. Its breathable film feels lightweight so dry and normal skin types appreciate the added moisture retention while oily skin benefits from its non-greasy finish. Those with very acne prone skin should note that any film former can potentially trap excess oil which might contribute to breakouts if cleansing is inadequate.
The polymer is fully synthetic and contains no animal-derived raw materials so it is considered suitable for both vegetarians and vegans.
Current safety assessments have not flagged Polyester-36 as a concern for women who are pregnant or breastfeeding when used topically. Still this is not medical advice and anyone who is expecting or nursing should review any skincare product with their healthcare provider to be sure it aligns with their individual needs.
Polyester-36 does not make skin more sensitive to sunlight and can even boost the staying power of sunscreens. It is also compatible with most other cosmetic ingredients and does not interfere with active treatments like retinoids or vitamin C.
Potential Side Effects/Adverse Reactions
Side effects from topical Polyester-36 can vary from person to person. The following list covers potential reactions yet most users will not experience them when the ingredient is used in a properly formulated product.
- Mild skin irritation such as redness itching or a transient stinging sensation
- Contact dermatitis in individuals who have a rare sensitivity or allergy to polyester type resins
- Clogged pores or increased breakouts in very acne prone skin due to the film trapping excess oil and debris
- Eye irritation like watering or burning if the product accidentally gets into the eyes
If any undesired reaction occurs discontinue use immediately and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 2 / 5
Polyester-36 itself is an inert polymer so it does not feed acne-causing bacteria, yet it does lay down a breathable film that can hold natural oils and environmental grime closer to the skin. This chance of trapping debris bumps its score slightly above non-comedogenic ingredients, though it is still considered low risk for most users. People who are already prone to congestion may notice an uptick in whiteheads if they do not cleanse thoroughly at the end of the day. Otherwise the ingredient is generally acceptable for breakout-prone skin when used in well-balanced formulas.
The comedogenic potential can rise if Polyester-36 is paired with heavy waxes or rich oils, so how the entire product is built matters more than the polymer alone.
Summary
Polyester-36 is a synthetic film former that creates a thin flexible layer on skin or hair, locking pigments in place, boosting water resistance and delivering light hold without a stiff feel. Its ability to keep makeup intact through sweat and humidity has earned it steady use in long wear foundations, eye products, sunscreens and some hair stylers although it is not as ubiquitous as older film formers like acrylates.
Overall safety data show it to be well tolerated by most skin types with a low risk of irritation or allergy and a mild comedogenic profile. As with any new cosmetic ingredient it is wise to patch test a small area first to confirm personal compatibility before applying a full-face or leave-on product.