What Is Polyurethane-100?
Polyurethane-100 is a synthetic polymer created by reacting a plant derived Dilinoleic Acid/Propanediol Copolymer with pentamethylene diisocyanate, then crosslinking the result to form a flexible three-dimensional network. The fatty acid part of the molecule comes from renewable vegetable oils, while the other building blocks are made in controlled laboratory settings.
Polyurethane materials first gained attention in the 1930s for industrial uses like coatings and foams. Over time chemists tailored smaller, more elegant versions for personal care and by the early 2000s brands began adding specific cosmetic grade polyurethanes such as Polyurethane-100 to improve product feel and performance.
The manufacturing process starts with carefully measuring and mixing the two main components under precise temperature and pH conditions. After the reaction completes, the mixture is purified, neutralized and turned into a smooth aqueous dispersion that blends easily into creams, gels or sprays.
Because it forms a thin, flexible film on the skin, Polyurethane-100 shows up in a variety of leave-on products. You will most often find it in hydrating masks, long-wear facial primers, anti-aging serums, tinted moisturizers, hair styling creams and even some water-resistant sunscreens where it helps lock active ingredients in place.
Polyurethane-100’s Cosmetic Benefits/Uses
In beauty formulas Polyurethane-100 contributes mainly in two practical ways
- Film Forming: It creates an invisible, breathable layer that helps products cling to the skin longer, boosts water resistance, reduces transfer and gives makeup a smoother finish
- Skin Conditioning: The flexible film traps moisture, leaving skin feeling soft and supple rather than tight or dry
Who Can Use Polyurethane-100
Polyurethane-100 works well for most skin types. Dry and normal complexions benefit from the light moisture-sealing film while oily or combination skin usually tolerates it because the polymer is lightweight and non greasy. Sensitive skin users generally experience few problems because the ingredient is inert and fragrance free, though anyone with a known allergy to polyurethane chemistry should avoid it.
The polymer is produced from renewable plant oils and laboratory made components, with no animal sourced materials involved, so it is considered suitable for vegans and vegetarians. As always check the full product label for other ingredients that might not meet personal standards.
Because Polyurethane-100 is a large molecule that mostly stays on the surface of skin, systemic absorption is expected to be negligible. Current data suggests no specific risk for pregnant or breastfeeding women, yet this is not medical advice. Anyone who is pregnant or nursing should show the product to a qualified healthcare provider before regular use.
The ingredient does not increase photosensitivity and can be worn during daylight without special precautions beyond normal sun protection. It is stable across a wide pH range and does not interfere with common actives like vitamin C, niacinamide or peptides.
Potential Side Effects/Adverse Reactions
Reactions to topical Polyurethane-100 vary from person to person. The following is a list of potential side effects that could occur, though they are unlikely for most users when the ingredient has been properly formulated and preserved.
- Mild transient redness or stinging, especially on freshly exfoliated skin
- Contact dermatitis in individuals already allergic to isocyanate based materials
- Clogged pores in rare cases when layered with heavy occlusive oils or waxes
- Flaking or film build-up if over applied or combined with other high level film formers
- Eye irritation if the product migrates into the ocular area before setting
If any of these reactions occur stop using the product and seek guidance from a qualified healthcare professional.
Comedogenic Rating
Rating: 1/5
Polyurethane-100 is a large, breathable polymer that sits on the skin’s surface instead of seeping into pores and it lacks the heavy oily residues that usually trigger breakouts. While it forms a film, that film is flexible and water dispersed, so it rarely traps sebum to the extent seen with thicker occlusives. On its own this makes it very low on the comedogenic scale. Minor risk may appear when the ingredient is blended with rich butters or waxes that already have higher ratings, which can create an environment more favorable for clogging.
Because of its lightweight nature, it is generally suitable for people who are prone to acne or breakouts.
Those who follow multi-layer routines should ensure each layer fully sets before adding the next, as stacking multiple film formers in quick succession can sometimes create a heavier feel that might contribute to congestion in very oily skin.
Summary
Polyurethane-100 works as a film former and skin conditioner, laying down a thin flexible web that improves water resistance, smooths makeup, boosts wear time and helps hold moisture close to the surface. Its polymer network gives products a silky finish without greasiness, which is why formulators reach for it in long wear cosmetics, hydrating masks and lightweight sunscreens.
While not as widely known as silicones or traditional emollients, its use has been steadily growing in modern clean and vegan-minded formulations thanks to its plant-derived fatty acid backbone and dependable performance.
Current safety data shows a low irritation profile and negligible absorption, so most users tolerate it well. As with any new skincare ingredient, a small patch test is a smart precaution to rule out individual sensitivities.