Cysteine HCl
AKA “Cystein chloride, CYSTEINE HYDROCHLORIDE, Cysteine chlorhydrate, cysteine-hcl, 3-Mercaptoalanine hydrochloride”
Synthetic
Ingredient Facts
Cysteine hcl
AKA: Cystein chloride, CYSTEINE HYDROCHLORIDE, Cysteine chlorhydrate, Cysteine-hcl, 3-Mercaptoalanine hydrochloride
Synthetic · Antioxidant · EWG: 4
Synthetic
Antioxidant
Skin Conditioner
Hair Care
Amino Acid
Medicated Active
Synthetic
Clean
Helps strengthen and condition hair while supporting natural antioxidant defenses. Works to smooth and straighten hair texture for a polished look.
Formula
C3H8ClNO2S
Mol. Weight
157.62
CAS #
52-89-1
Form
Powder
See origin →
Functions
Antioxidant
Fights free radicals — the unstable molecules from UV, pollution, and stress that break down collagen and cause premature aging.
Hair Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Hair Waving Or Straightening
Reducing
Neutralizes Free Radicals
Traditional Use
The hydrochloride salt form of cysteine, developed as a more stable and soluble version for cosmetic formulations. Used since the 1980s in skincare and haircare products to improve stability while maintaining cysteine's antioxidant benefits.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR