Stearyl Betaine

AKA: Stearylbetaine, N-Stearylbetaine, Lonzaine 18S, Stearyldimethylbetaine, Stearyl dimethyl glycine, (Carboxymethyl)octadecyldimethylammonium hydroxide inner salt
Plant-Derived
Cleanser
Skin Conditioner
Hair Care
Not Clean
OriginDerived from coconut oil or palm kernel oil through fatty acid extraction. Synthesized by quaternization of the fatty amine with betaine through chemical reaction.
(Carboxylatomethyl)dimethyl(octadecyl)ammonium
Formula
C22H45NO2
Mol. Weight
355.60
CAS #
820-66-6
Form
Liquid
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
Functions
Antistatic
Cleansing
Makes oil and water mix so dirt, makeup, and sunscreen can actually be washed away. The reason your face wash foams.
Foaming
Hair Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Cleansing
Makes oil and water mix so dirt, makeup, and sunscreen can actually be washed away. The reason your face wash foams.
Foam Boosting
Viscosity Controlling
Locks in moisture
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.
EWG
4
CIR
Safe as used
Pregnancy
Yes
Concentration Guide
CIR's newest survey reports no concentration of use.
CIR · report published 2018
Regulatory Status
USA✔ permitted
EU⚠ restricted
JAPAN⚠ restricted
CANADA⚠ restricted
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR