Polyurethane-55

Synthetic

Skin Conditioner

Not Clean

Polyurethane-55 is the polymer formed by the reaction of Poly(1,4-Butanediol)-28, Poly(1,4-Butanediol)-14, and 1,3-bis(isocyanatomethy)cyclohexane. The polymer is capped with 4-hydroxybutyl acrylate.

Functions

Nail Conditioning

A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.

Strengthens nails

Traditional Use

Synthetic polymer developed in the mid-20th century. Used in cosmetics as a film-forming and conditioning agent in hair and skin products.

EWG

CIR

Safe as used

Pregnancy

Yes

CIR Safety Findings

Not a Sensitizer

medical-approval

all-shades-safe

Regulatory Status

USA✔ permitted

EU⚠ restricted

JAPAN⚠ restricted

CANADA⚠ restricted

Regulatory Agencies

EWG CIR FDA EU COSING Health Canada

Skin Types

●all-skin-types

Best For

General

Pregnancy & Breastfeeding Safe

Yes

The paper trail

🔬Peer-reviewednone on file

⚖️Regulatory1 listing →

🛡️Safety-assessed1 review →

Counts, not a verdict. A listing isn't a study. The trail, you decide.

Verified Jun 2026

Data: CosIng · EWG · CIR