What Is Polyurethane-5?
Polyurethane-5 is a man-made copolymer created by reacting the building blocks hexylene glycol, neopentyl glycol, adipic acid and isophorone diisocyanate. When these small molecules are linked together they form a flexible network that behaves like a thin plastic film once it dries on skin or hair. The ingredient was first explored in industrial coatings for its toughness and water resistance, then cosmetic chemists noticed these same traits could improve makeup and skin care that needed to last through heat, sweat and daily wear. Production starts with carefully measured amounts of the glycols and acid combined with the diisocyanate under controlled heat. After the chains reach a set length the mixture is neutralized, dispersed in water and filtered until it meets cosmetic grade standards.
You will most often see Polyurethane-5 in products that promise long wear or smudge resistance such as liquid foundations, mascaras, eyeliners, brow gels, lip colors, primers, sunscreens, hair styling gels and certain sheet or peel-off masks.
Polyurethane-5’s Cosmetic Benefits/Uses
Polyurethane-5 is prized for one main role in beauty formulas.
Film forming: Once the product is applied the ingredient dries into an invisible flexible layer that clings to the surface. This film locks pigments in place, helps active ingredients stay put longer, boosts water and sweat resistance, reduces flaking in mascara and improves transfer resistance in foundation or lipstick. The result is makeup or skin care that looks fresh for more hours without frequent touch-ups.
Who Can Use Polyurethane-5
Polyurethane-5 is generally well tolerated by normal, dry, combination and oily skin because it forms a breathable film rather than a heavy, greasy layer. Extremely sensitive or highly acne-prone users may notice occasional build-up or a tight feeling if the product is applied in thick layers or not removed thoroughly, although this is uncommon.
The polymer is fully synthetic and contains no animal-derived ingredients, so it is suitable for vegans and vegetarians. Animal testing policies depend on the brand and region, so those concerned should verify a company’s cruelty-free status.
No published data link topical Polyurethane-5 with risks during pregnancy or breastfeeding. It stays on the surface of skin and is not expected to penetrate or enter the bloodstream. That said, this is not medical advice and anyone who is pregnant or nursing should ask a doctor before adding new cosmetics to their routine.
The ingredient does not absorb UV light and is not known to cause photosensitivity. It can actually help shield makeup from sweat and water but offers no sun protection on its own.
Potential Side Effects/Adverse Reactions
Responses to Polyurethane-5 vary with individual skin chemistry and product formulation. The effects listed below are possible yet unlikely for most users when the ingredient is used correctly.
- Contact irritation such as mild redness, itching or stinging
- Allergic rash in individuals already sensitized to polyurethane resins or isocyanates
- Temporary clogged pores or breakouts if heavy layers are left on very oily skin
- Eye watering or stinging if mascara or liner containing it is not removed before sleep
- Scalp or hair stiffness with overuse in styling gels or sprays
If any discomfort or reaction occurs stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 1/5. Polyurethane-5 is a lightweight film former that stays on the surface of skin rather than seeping into pores and it contains no oils or waxes that would normally clog them. Only if thick layers are left on for days could residue mix with sebum and bump the risk slightly which keeps it from scoring a perfect zero.
Most acne-prone users can safely use products with Polyurethane-5.
If you rely on long-wear makeup, a thorough nightly cleanse helps prevent any build-up that might encourage congestion over time.
Summary
Polyurethane-5 is valued for forming a flexible film that locks color in place, boosts water and sweat resistance and cuts down on smudging, flaking and transfer so makeup and skin treatments last longer.
The ingredient is popular in long-wear cosmetics like mascaras, eyeliners, foundations and peel-off masks yet remains absent from many basic skincare staples.
It is considered low risk with minimal irritation or comedogenic concerns for most people. As with any new ingredient, a quick patch test is wise before adding a Polyurethane-5 product to your daily lineup.