Ammonium Thioglycolate
molecular structure · PubChem
AKA: 5421-46-5, Ammonium mercaptoacetate, Thioglycolic acid ammonium salt, Thiofaco A-50, Acetic acid, Monoammonium salt, Ammonium thioglycollate, Ammonium sulfanylacetate, USAF MO-2, HSDB 7167
Synthetic
Not Clean
Based on the available data, the CIR Expert Panel concluded that ... Ammonium Thioglycolate is safe for use in hair straighteners, permanent waves, tonics, dressings, and so forth, wave sets, other non-coloring hair products, and hair dyes and colors, as described in this safety assessment, at concentrations up to 15.2% (as Thioglycolic Acid). Hairdressers should avoid skin contact and minimize consumer skin exposure.
Solubility Miscible (NTP, 1992)
Formula
C2H7NO2S
Mol. Weight
109.15
CAS #
5421-46-5
Form
Liquid
State
Ammonium thioglycolate is a colorless to faint pink liquid with a repulsive, skunk-like odor. (NTP, 1992)
Functions
Depilatory
Hair Waving Or Straightening
Reducing
Moisturizing
Strengthens Barrier
Changes hair texture
Removes unwanted hair
Chemical reduction
Traditional Use
Developed in the early-to-mid 20th century as a reducing agent. Became the standard ingredient for chemical hair relaxing and permanent wave treatments, replacing traditional alkaline-based hair straightening methods.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR