Polyurethane-51

AKA: Polyurethane polymer, Film-forming agent

Synthetic

Skin Conditioner

Not Clean

OriginPolyurethane-51 is synthesized from polyols and isocyanates, which are petroleum-derived chemical precursors. It is produced through step-growth polymerization, where isocyanates react with polyols under controlled conditions to form the polymer chain.

Polyurethane-51 is a copolymer made by reacting 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (HEMA), 1,2-Butanediol (q.v.), poly(1,4-butanediol) and 1,3-bis(isocyanatomethyl)cyclohexane.

Skin Types

●all-skin-types

Best For

General

Pregnancy & Breastfeeding Safe

Yes

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

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.

EWG

CIR

Safe as used

Pregnancy

Yes

Concentration Guide

CIR lists it as not reported to be in use.

CIR · report published 2017

Regulatory Status

USA✔ permitted

EU⚠ restricted

JAPAN⚠ restricted

CANADA⚠ restricted

Regulatory Agencies

EWG CIR FDA EU COSING Health Canada

Verified Jun 2026

Data: CosIng · EWG · CIR