What Is Polyurethane-39?
Polyurethane-39 is a synthetic copolymer created by linking PEG-140 with hexamethylene diisocyanate, then finishing the chain with surfactant-like side groups known as C12-14 Pareth-10, C16-18 Pareth-11 and C18-20 Pareth-11. This structure gives the material a balance of water-loving and oil-loving parts, which lets it blend smoothly into many cosmetic bases. Polyurethanes first found fame in the 1930s as durable foams and coatings; chemists later adapted the chemistry to produce lighter, more flexible versions fit for skin care. Polyurethane-39 is manufactured in closed reactors where the PEG segment reacts with the diisocyanate under controlled heat and stirring, after which the Pareth chains are attached to cap the polymer and control its texture. The finished ingredient usually appears as a clear to slightly hazy liquid that dissolves easily in water. You will most often see Polyurethane-39 in lightweight gels, sheet mask essences, refreshing moisturizers, hair styling creams and color cosmetics like liquid foundation where a silky, non-sticky feel is key.
Polyurethane-39’s Cosmetic Benefits/Uses
Polyurethane-39 serves mainly as a viscosity-controlling agent, meaning it fine-tunes how thick or thin a product feels. By adjusting flow, it helps formulators create a lotion that glides without running, a serum that stays put during application or a gel that spreads evenly across the face. Stable viscosity also keeps pigments and actives evenly dispersed, which supports consistent performance and shelf life.
Who Can Use Polyurethane-39
Because Polyurethane-39 is a neutral, water-soluble polymer that leaves little residue on the skin it tends to suit most skin types, from dry and mature to oily and combination. Those with very sensitive or compromised skin usually tolerate it well since it is non-reactive and free of common irritants; however, extremely sensitised skin should still monitor for any discomfort simply because every complexion is different.
The ingredient is fully synthetic with no animal-derived raw materials, making it appropriate for vegans and vegetarians. Manufacturing does not rely on animal testing in regions that follow current cosmetic regulations though finished products may vary by brand policy.
No data indicate that topical Polyurethane-39 poses a specific risk to women who are pregnant or breastfeeding. That said this information is educational only and any expectant or nursing individual should review new skincare purchases with a qualified medical professional to be on the safe side.
Polyurethane-39 does not absorb UV light or make skin more sun sensitive, so there is no added risk of photosensitivity during daytime wear. It is also fragrance free and unlikely to interact with other active ingredients, giving formulators flexibility to pair it with acids, retinoids or antioxidants without instability.
Potential Side Effects/Adverse Reactions
Side effects and reactions to the topical use of Polyurethane-39 can vary from person to person. The points below outline potential issues yet they are uncommon when the ingredient is properly formulated and used as intended. Most users will experience no negative effects.
- Mild skin irritation such as redness itching or a transient stinging sensation
- Contact dermatitis in individuals already sensitised to polyethylene glycols or isocyanate residues
- Eye irritation if the raw material or a product containing it accidentally enters the eyes
- Rare clogging or buildup on very oily skin if used in heavy multiple-layer routines
Should any of these reactions occur stop using the product immediately and consult a healthcare professional or dermatologist for guidance.
Comedogenic Rating
Rating: 0 / 5
Polyurethane-39 is a large, water-soluble polymer that sits on the skin surface and rinses away easily, so it does not trap oil or debris inside pores. It lacks the heavy fatty acids and waxy residues typically linked with pore blockage, which is why formulators view it as non-comedogenic.
Suitable for acne-prone or breakout-prone skin.
Because this ingredient often appears in lightweight gels or serums it can even help thin out richer formulas, indirectly making a product feel less occlusive.
Summary
Polyurethane-39 is used mainly to control viscosity, helping lotions, gels and creams achieve a silky glide while keeping pigments and actives evenly suspended. Its amphiphilic structure lets it blend into both water and oil phases, giving formulators a reliable way to fine-tune texture without heaviness.
The ingredient is still a relative niche player compared with classic thickeners like carbomers or xanthan gum, yet brands that want a smooth, modern skin feel are steadily adopting it.
Current data show Polyurethane-39 is low risk for irritation or sensitization, making it broadly safe for everyday use. As with any new cosmetic, performing a quick patch test when trying a product that contains it is a smart precaution.