Potassium Undecylenate
molecular structure · PubChem
AKA: 6159-41-7, Undecylenic acid, Potassium salt, POTASSIUM UNDECYLENATE [INCI]
Synthetic
Preservative
Cleanser
Emulsifier
Plant Oil
Not Clean
Undecylenic acid, potassium salt
Formula
C11H19KO2
Mol. Weight
222.37
CAS #
6159-41-7
Form
Powder
Functions
Preservative
Keeps your product from growing bacteria, mold, or yeast. Without these, that jar of cream becomes a petri dish in about a week.
Cleansing
Makes oil and water mix so dirt, makeup, and sunscreen can actually be washed away. The reason your face wash foams.
Emulsifying
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Preserves Formula
Cleansing Surfactant
Emulsifier
Lifts away dirt and oil
Prevents microbial growth
Mixes oil and water
Traditional Use
Undecylenic acid, derived from castor oil, was first isolated in the 1940s and developed as an antifungal agent. Potassium undecylenate represents the salt form created to improve stability and efficacy in modern skincare and antifungal products.
EWG
4
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Concentration Guide
0.2%
0%0%
Reg. Limit
EU regulatory limit: 0.2%. Source: EU Cosmetics Regulation (EC) 1223/2009, Annex V (Preservatives), Entry 18.
Regulatory Agencies
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed1 review →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR