murphySodium Undecylenate
AKA: 3398-33-2, Sodium undec-10-enoate, Undecylenic Acid Sodium Salt, 10-Undecenoic acid, Sodium salt, 10-Undecenoic, AI3-19721
Synthetic
Preservative
Cleanser
Emulsifier
Not Clean
OriginDerived from undecylenic acid, a fatty acid within the synthetic surfactant and preservative chemical family. Synthesized through the neutralization of undecylenic acid with sodium hydroxide or sodium carbonate.
The CIR Expert Panel concluded that the following ingredients are safe in the present practices of use andconcentration described in the safety assessment when formulated to be non-irritating and non-sensitizing, which may be basedon a QRA...Sodium Undecylenate...
Formula
C11H19NaO2
Mol. Weight
206.26
CAS #
3398-33-2
State
Solid; [Sigma-Aldrich MSDS]
Skin Types
●all-skin-types
Best For
Acne
Pregnancy & Breastfeeding Safe
Yes
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.
Surfactant Cleansing
Surfactant Emulsifying
Anti-Inflammatory
Antimicrobial
Fights Acne
Lifts away dirt and oil
Prevents microbial growth
Mixes oil and water
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 Sensitizer
1 study / 1 not sensitizing (CIR 777)
Eye Irritant in Testing
1 study / 1 irritating / reactions mild to moderate (CIR 777)
Concentration Guide
0%50%100%
Reg. limit 0.2%
CIR's newest survey reports no concentration of use.
CIR · 2016 survey
EU regulatory limit: 0.2%. Source: EU Cosmetics Regulation (EC) 1223/2009, Annex V (Preservatives), Entry 18.
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR