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Ammonium Thioglycolate
AKA “Ammonium mercaptoacetate, Thioglycolic acid ammonium salt, Thiofaco A-50, Acetic acid, monoammonium salt, Ammonium thioglycollate, ammonium sulfanylacetate, USAF MO-2”
Synthetic
Ingredient Facts
Ammonium thioglycolate
AKA: Ammonium mercaptoacetate, Thioglycolic acid ammonium salt, Thiofaco A-50, Acetic acid, Monoammonium salt, Ammonium thioglycollate, Ammonium sulfanylacetate, USAF MO-2
Synthetic · Depilatory · EWG: 5
Synthetic
Synthetic
Clean
A keratin-breaking agent that helps relax or remove hair. Used in professional hair straightening and wave treatments to reshape hair texture.
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)
See origin →
Functions
Depilatory
Hair Waving Or Straightening
Reducing
Moisturizing
Locks in moisture to keep skin soft and supple throughout the day
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
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Caution
EWG
5
CIR
Safe w/Qualifications
Pregnancy
Caution
CIR Safety Findings
ewg-5
medical-approval
all-shades-safe
Mild Irritant
Regulatory Status
USA✔ permitted
EU✔ permitted
JAPAN✔ permitted
CANADA✔ permitted
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl
Burnett CL, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr et al.
International journal of toxicology, 2009
→
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 Amended Report on the Safety Assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl T
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
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)
→
Ammonium Thioglycolate
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)
→
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
→
Ammonium Thioglycolate
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
→
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR