Methyl Thioglycolate
AKA “Methyl mercaptoacetate, Methyl 2-mercaptoacetate, Thioglycolic acid methyl ester, Methylthioglycolate, Acetic acid, methyl ester”
Synthetic
Ingredient Facts
Methyl thioglycolate
AKA: Methyl mercaptoacetate, Methyl 2-mercaptoacetate, Thioglycolic acid methyl ester, Methylthioglycolate, Acetic acid, Methyl ester
Synthetic · Hair Waving Or Straightening · EWG: 4
Synthetic
Synthetic
Clean
A chemical that helps reshape hair structure, used in permanent wave and straightening treatments to create lasting style changes.
Formula
C3H6O2S
Mol. Weight
106.15
CAS #
2365-48-2
Form
Liquid
State
Colorless liquid with a stench; [MSDSonline]
See origin →
Functions
Hair Waving Or Straightening
Reducing Agent
Anti-Aging Benefits
Antioxidant Protection
Reduces Inflammation
Changes hair texture
Traditional Use
Developed in the mid-20th century as a chemical depilatory and permanent wave setting agent. Created to replace safer but less effective historical hair-removal methods like sulfides and lyes.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Caution
RIFM fragrance ingredient safety assessment, pentanedioic acid, 1,5-dimethyl ester, CAS Registry Number 1119-40-0.
Api AM, Belsito D, Botelho D, Browne D, Bruze M et al.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2018
Safety Assessment of Tetrasodium Glutamate Diacetate and Beta-Alanine Diacetic Acid as Used in Cosmetics.
Burnett CL, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2025
Safety Assessment of Tetrasodium Glutamate Diacetate and Beta-Alanine Diacetic Acid as Used in Cosmetics.
Burnett CL, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2025
Sodium Dehydroacetate and Dehydroacetic Acid.
Cherian P, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2024
Sodium Dehydroacetate and Dehydroacetic Acid.
Cherian P, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2024
Final Report on the Safety Assessment of Sodium Dehydroacetate and Dehydroacetic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Safety Assessment of Tetrasodium Glutamate Diacetate and Beta-Alanine Diacetic Acid as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Sodium Dehydroacetate and Dehydroacetic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Acetic Acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
Beta-Alanine Diacetic Acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
dehydroacetic acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
Methyl Thioglycolate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Acetic acid and the skin: a review of vinegar in dermatology.
Elhage KG, St Claire K, Daveluy S
International journal of dermatology, 2022
Acetic acid and the skin: a review of vinegar in dermatology.
Elhage KG, St Claire K, Daveluy S
International journal of dermatology, 2022
Acetic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
dehydroacetic acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Potential application of novel liquid crystal nanoparticles of isostearyl glyceryl ether for transdermal delivery of 4-biphenyl acetic acid.
Fujii MY, Asakawa Y, Fukami T
International journal of pharmaceutics, 2020
Preparation of (13)C-labeled ceramide by acetic acid bacteria and its incorporation in mice.
Fukami H, Tachimoto H, Kishi M, Kaga T, Waki H et al.
Journal of lipid research, 2010
Trichloroacetic acid
Health Canada
Health Canada Cosmetic Ingredient Hotlist
Synthesis of mixed esters of ascorbic acid using methyl esters of palm and soybean oils.
Hsieh HJ, Chen JW, Giridhar R, Wu WT
Preparative biochemistry & biotechnology, 2005
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR