What Is Polyurethane-93?
Polyurethane-93 is a synthetic polymer created by first reacting succinic acid, 1,4-butanediol, neopentyl glycol and isophorone diisocyanate to build a flexible prepolymer. That prepolymer is then linked with sodium N-(2-aminoethyl)-2-aminoethanesulfonate and isophorone diamine, giving the finished material its water-friendly and film-forming character. The result is a clear, lightweight resin that disperses well in water and bonds smoothly to hair or skin surfaces.
Polyurethane chemistry has been around since the 1940s, mostly for coatings and foams. As styling products evolved in the 1990s formulators noticed that certain polyurethane structures formed breathable, durable films that outperformed older fixatives like PVP. Polyurethane-93 emerged from that search thanks to its balance of flexibility and washability, and it began appearing in salon sprays and setting lotions in the early 2000s. Today it is produced in closed reactors where temperature and pH are tightly controlled, followed by neutralization and filtration to yield a low-odor aqueous dispersion suitable for cosmetics.
You will most often find Polyurethane-93 in hair sprays, mousses, styling creams, gels, leave-in conditioners and brow setters. It can also appear in long-wear makeup primers or liquid eyeliners where a soft yet resilient film is useful.
Polyurethane-93’s Cosmetic Benefits/Uses
Formulators turn to Polyurethane-93 for three key reasons
- Film forming – it dries to a thin flexible layer that resists humidity and friction helping styles or makeup stay intact longer
- Hair conditioning – the polymer smooths the cuticle surface so strands feel softer look shinier and are easier to comb
- Hair fixing – its strong yet elastic hold locks styles in place without leaving hair overly stiff or flaky
Who Can Use Polyurethane-93
Polyurethane-93 is lightweight nonocclusive and water dispersible so it suits most skin and scalp types including oily combination dry and even sensitive skin that struggles with heavier waxes or oils. People with very reactive or allergy-prone skin should still check the full ingredient list to be sure they are not sensitive to any accompanying preservatives or fragrances.
The polymer is made entirely from synthetic building blocks with no animal-derived substances or by-products which makes it acceptable for both vegans and vegetarians.
Because Polyurethane-93 is a high-molecular-weight film former it stays on the surface and is not expected to penetrate into deeper tissues. Current safety assessments have not flagged any reproductive or developmental concerns so products containing it can generally be used during pregnancy or while breastfeeding. This is not medical advice and anyone who is pregnant or nursing should ask their doctor before adding new hair or skincare products just to be safe.
The ingredient is not known to cause photosensitivity and it does not interfere with sunscreen filters so there are no special sun-exposure precautions tied to its use.
Potential Side Effects/Adverse Reactions
Individual responses to topical Polyurethane-93 can vary. The points below describe potential side effects that have been reported in rare cases; most users will not experience them when the ingredient is formulated and used correctly.
- Mild skin or scalp irritation especially in people with an existing sensitivity to synthetic resins
- Contact dermatitis triggered by trace residual monomers or additives left after manufacturing
- Eye irritation if aerosolized product accidentally gets into the eyes during application
- Respiratory discomfort from inhaling fine spray particles in poorly ventilated spaces
- Build-up on hair shafts leading to dullness or limp texture if the product is not washed out periodically
If any burning itching swelling or breathing difficulty occurs stop using the product immediately and seek medical advice.
Comedogenic Rating
Rating: 1/5
Polyurethane-93 sits on the surface as a high-molecular-weight film that is water dispersible and nonocclusive so it is highly unlikely to block pores. Its low oil content and good rinse-off profile further reduce the chance of comedones forming. Because it does leave a flexible coating there is a small theoretical risk of residue building up in very oily areas which is why it is not scored a perfect zero.
In practical terms Polyurethane-93 is generally considered suitable for acne-prone or breakout-prone skin.
No interactions with acne medications or actives like benzoyl peroxide or salicylic acid have been documented.
Summary
Polyurethane-93 is a synthetic polymer prized for three main jobs: forming an invisible flexible film, smoothing and conditioning hair strands and delivering reliable yet elastic hold. It accomplishes these tasks by creating a water-friendly resin network that clings evenly to hair or skin then dries into a breathable layer that resists humidity and friction while rinsing away with standard shampoo or cleanser.
While not a household name it has carved out a steady niche in professional sprays, mousses, gels and some long-wear makeup where formulators want strong hold without the crunch associated with older resins.
Current safety reviews rate Polyurethane-93 as low risk for irritation or systemic absorption. Most people can use it daily without trouble but as with any new cosmetic ingredient doing a quick patch test helps catch rare sensitivities before full use.