Undecylenoyl Phenylalanine

Undecylenoyl Phenylalanine molecular structure
molecular structure · PubChem
AKA: 175357-18-3, Sepiwhite msh, Undecylenoylphenylalanine, Sepiwhite msh QD, N-Undecenoyl-L-phenylalanine, L-Phenylalanine, Sepiwhite
Synthetic
Skin Conditioner
Amino Acid
Clean
L-Phenylalanine, N-(1-Oxo-10-Undecenyl)-
Effective at 1.25%
Formula
C20H29NO3
Mol. Weight
331.40
CAS #
175357-18-3
Form
Powder
Functions
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Locks in moisture
Traditional Use
A synthetic cosmetic ingredient made by conjugating undecylenic acid with the amino acid phenylalanine. Developed to combine antimicrobial properties with amino acid skin benefits.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Concentration Guide
0.5%
2.0%
0%3%
Reported use
CIR reported use: 0.5-2
Regulatory Status
USA✔ permitted
EU⚠ restricted
JAPAN⚠ restricted
CANADA⚠ restricted
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR