Quaternium-18
AKA: Dimethyl dioctadecyl ammonium chloride, Stearalkonium chloride
Synthetic
Cleanser
Skin Conditioner
Hair Care
Plant Oil
Not Clean
Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, chlorides
CAS #
61789-80-8
Form
Liquid
Functions
Antistatic
Hair 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.
Reduces Static
Conditions Hair
Cleansing Surfactant
Locks In Moisture
Lifts away dirt and oil
Reduces flyaways
Softens and detangles hair
Traditional Use
A quaternary ammonium compound developed in the mid-20th century as a synthetic conditioning and antistatic agent for hair and skincare products. Designed to replace natural oils while providing improved stability and consumer appeal.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: CosIng · EWG · CIR