AMMONIUM THIOGLYCOLATE
Commonly Found In
Overview
Ammonium thioglycolate is the primary active ingredient in permanent wave (perm) and hair-straightening solutions. It works by reducing disulfide bonds in hair keratin, allowing the hair to be reshaped. The EU restricts it under Annex III; Japan permits it with concentration limits. It can cause significant scalp and skin irritation at working concentrations.
Also known as: ammonium mercaptoacetate, thioglycolic acid ammonium salt, ammonium 2-mercaptoacetate
Key Benefits
No skin benefit; functions as a reducing agent to break hair disulfide bonds for perming and straightening. Studies suggest significant scalp and skin irritation potential at functional concentrations.
Supporting Research
- β’ CIR Expert Panel β Safety Assessment of Thioglycolic Acid and its Salts: Assessed safe at EU-regulated concentrations with proper use instructions
- β’ EU Annex III/2a: Specifies concentration limits by product type for hair waving/straightening and depilatories
Skin Compatibility Ratings
Comedogenic Rating
Non-comedogenic; aqueous reducing agent used in hair waving and straightening at high pH.
Source: CIR Expert Panel safety assessment
Irritancy Rating
Significant irritancy to scalp and skin at functional concentrations used in perm and depilatory applications; requires pH and concentration controls
Source: CIR Expert Panel; EU Annex III classification
Typical Use Concentration
Range
1β8% (as thioglycolic acid equivalent)
Optimal
Varies by EU Annex III/2a product category
EU Annex III/2a sets maximum concentrations by product type (general/professional use). Japan and US set their own limits.
Works Well With / Avoid
Works Well With
Avoid Combining
EU Annex III/2a regulates specific concentration limits by product category. Used in two-step process: reducing (thioglycolate) then oxidizing (H2O2) to reset disulfide bonds. Not for damaged or sensitized scalp.
Commonly Found In
Global Regulation Summary
Overview of current status across major international markets.
Detailed Regional Status
| Region | Status | Max Conc. | Conditions | Source |
|---|---|---|---|---|
| πͺπΊ EU | Banned | - | - | Official β |
| πΊπΈ USA | Allowed | - | - | Official β |
| π―π΅ Japan | Allowed | - | - | Official β |
| π°π· Korea | Unknown | - | - | Official β |
| π¬π§ UK | Restricted | - | Follows EU regulations (III/2a) | Official β |
π Why Regulations Differ
EU Annex III/2a provides detailed concentration and pH restrictions by product type. Japan permits use with its own concentration limits. US permits use with FDA monitoring. Scalp irritation and sensitization data inform regulatory limits.
Regulation Analysis
Regional Agreement
Banned in EU but allowed in USA, Japan.
Category Comparison
There are 17 ingredients in the DEPILATORY category. 100% are banned in at least one major market.
Strictness Ranking
πΏ Natural Sources
Not found in nature. A synthetic salt of thioglycolic acid and ammonia. However, thioglycolic acid itself can be found in trace amounts in some biological systems.
π How It's Made
Produced by neutralizing thioglycolic acid with ammonia (ammonium hydroxide). Thioglycolic acid is made by reacting chloroacetic acid with sodium hydrosulfide.
π Uses in Cosmetics
Used in permanent wave solutions (typically 5β10% thioglycolic acid equivalent) and hair depilatories. Breaks disulfide bonds in hair keratin to allow reshaping (curling or straightening). EU Annex III provides specific concentration limits by product type.
π¬ Other Applications
Used in leather processing, rubber manufacturing, and as a chemical reagent in analytical chemistry. Also used in some depilatory (hair removal) creams.
π‘ Fun Facts
- β’ Ammonium thioglycolate is the active ingredient in most permanent wave (perm) solutions β it works by breaking the disulfide bonds in hair keratin
- β’ The same chemistry that curls hair can also straighten it β Japanese and Brazilian straightening treatments use similar thioglycolate-based chemistry
- β’ The distinctive strong smell of perm solutions comes from the ammonia and sulfur compounds in this ingredient
Data Sources
- β’ EU Cosmetics Regulation 1223/2009 Annex III entry 2a
- β’ CIR Expert Panel β Safety Assessment of Thioglycolic Acid and Salts
- β’ Japan MHLW β hair perm concentration limits
Last data verification: 2026-04-16
Related Ingredients
Learn More
Frequently Asked Questions
Why is AMMONIUM THIOGLYCOLATE banned in the EU but allowed in the US?
The EU follows a precautionary principle, banning AMMONIUM THIOGLYCOLATE under III/2a due to potential safety concerns. The US FDA has not found sufficient evidence to prohibit its use, allowing it under different safety assessment standards. This reflects differing regulatory philosophies between the two regions.
Why is AMMONIUM THIOGLYCOLATE banned in the EU but allowed in Japan?
The EU prohibits AMMONIUM THIOGLYCOLATE (III/2a) based on their strict safety criteria. Japan's Ministry of Health, Labour and Welfare (MHLW) has evaluated the ingredient and permits its use, potentially with different safety data or usage conditions.
What is AMMONIUM THIOGLYCOLATE used for in cosmetics?
AMMONIUM THIOGLYCOLATE is primarily used for depilatory in cosmetic products. It also serves as hair waving or straightening, reducing. The ingredient is commonly found in various cosmetic and personal care products.
Which countries regulate AMMONIUM THIOGLYCOLATE?
AMMONIUM THIOGLYCOLATE is banned in EU. It has concentration limits or usage restrictions in UK. The ingredient is freely allowed in JP, US.
Are there alternatives to AMMONIUM THIOGLYCOLATE?
Due to regulatory restrictions on AMMONIUM THIOGLYCOLATE, cosmetic manufacturers often use alternative ingredients with similar functions. For depilatory, alternatives may include other approved ingredients in the same category. Consult product labels for specific formulations, and look for products compliant with your region's regulations.
Disclaimer
The information on this website is for educational and informational purposes only and is not intended as medical advice. While we strive for accuracy based on official government databases, cosmetic regulations change frequently. Always consult with a qualified professional or refer to the latest official regulatory documents for compliance. We are not responsible for any actions taken based on the information provided here.