murphyPolyurethane-21
molecular structure · PubChem
AKA: PU-21
Synthetic
Occlusive
Not Clean
OriginPolyurethane-21 is synthesized from polyols and isocyanates, which are petrochemical-derived compounds. It is produced through condensation polymerization, where these components react to form a flexible polymer chain.
Methylenedicyclohexanediisocyanate, polymer with 2,2-di(hydroxymethyl)propanoic acid and 2,2'-oxybisethanol/2-oxepanone copymer, tris(2-hydroxyethyl)amine salts
CAS #
-
Form
Powder
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
Functions
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Creates Protective Barrier
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
4
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Skin Irritant
3 studies / 3 not irritating (CIR 736)
Not a Sensitizer
2 studies / 2 not sensitizing (CIR 736)
Not an Eye Irritant
1 study / 1 not irritating (CIR 736)
Concentration Guide
CIR lists it as not reported to be in use.
CIR · report published 2017
Regulatory Agencies
Verified Jun 2026
Data: CosIng · EWG · CIR