Ethyl Thioglycolate

AKA: 623-51-8, Ethyl 2-mercaptoacetate, Ethyl mercaptoacetate, USAF EK-2070, Thioglykolsaeure-aethylester, Ethyl .alpha.-mercaptoacetate, Acetic acid, Ethyl ester, 2-mercaptoacetic acid ethyl ester
Synthetic
Not Clean
OriginProduced from ethylene glycol and thioglycolic acid, members of the thiol and hydroxyl chemical families. Synthesized through esterification reaction between thioglycolic acid and ethanol under controlled conditions.
Based on the available data, the CIR Expert Panel concluded that ... Ethyl 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.
Formula
C4H8O2S
Mol. Weight
120.17
CAS #
623-51-8
Form
Liquid
State
Colorless liquid with a stench; [Alfa Aesar MSDS]
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
Functions
Depilatory
Hair Waving Or Straightening
Reducing
Moisturizing
Strengthens Barrier
Changes hair texture
Removes unwanted hair
Chemical reduction
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
Caution
Concentration Guide
CIR lists it as not reported to be in use.
CIR · report published 2009
Regulatory Status
USA✔ permitted
EU✔ permitted
JAPAN✔ permitted
CANADA✔ permitted
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR