Is Thioglycolic Acid safe in cosmetics?
Thioglycolic Acid has a safety rating of "MODERATE" in our database. EU status: prohibited. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
Thioglycolic Acid
Also known as: Acetic acid, mercapto-, 4-03-00-00600, BRN 0506166, EINECS 200-677-4, Glycolic acid, thio- (+9 more)
INCI: THIOGLYCOLIC ACID
Thioglycolic Acid (CAS 68-11-1) is a cosmetic cosmetic ingredient functioning as Depilatory, Hair Waving/Straightening, Keratolytic, Reducing Agent. NOAEL 129 mg/kg bw/day (PDF-verified against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: prohibited, max 5.0%. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 68-11-1 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
Thioglycolic Acid is prohibited in EU cosmetics at max 5.0% but has active industrial GHS classifications (H301, H311, H314, H317, H318, H330, H331, H312).
Source: Cosmetics: ingredients.eu status/eu max; Chemicals: ghs classifications.signal word/hazard statement code
Function
Depilatory, Hair Waving/Straightening, Keratolytic, Reducing Agent
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
2-sulfanylacetic acid
InChIKey
CWERGRDVMFNCDR-UHFFFAOYSA-N
Regulatory Status
EU EU Status
prohibited
EU Max Conc.
5.0%
US US Status
permitted
US Notes
Permitted; no specific FDA concentration cap but must be safe under intended conditions of use
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Thioglycolic Acid.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Thioglycolic Acid. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =0.044 mg/kg bw | dermal | rat | dermal absorption | SCCS Opinion |
| NOAEL | =0.044 mg/kg bw | dermal | rat | dermal absorption | SCCS Opinion |
| NOAEL | =0.044 mg/kg bw | dermal | rat | dermal absorption | SCCS Opinion |
| NOAEL | =0.044 mg/kg bw | dermal | rat | dermal absorption | SCCS Opinion |
| NOAEL | =1.66 mg/kg bw | dermal | rat | NOAEL study | SCCS Opinion |
| NOAEL | =1.66 mg/kg bw | dermal | rat | NOAEL study | SCCS Opinion |
| NOAEL | =1.66 mg/kg bw | dermal | rat | NOAEL study | SCCS Opinion |
| NOAEL | =1.66 mg/kg bw | dermal | rat | NOAEL study | SCCS Opinion |
| NOAEL | =7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS Opinion |
| NOAEL | =7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS Opinion |
GHS Hazard Classification
Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.
Short-term Exposure Effects
The substance is corrosive to the eyes, skin and respiratory tract. Inhalation of the vapour may cause lung oedema. Exposure could cause death. The effects may be delayed. Medical observation is indicated. See Notes.
Routes of Exposure
The substance can be absorbed into the body by inhalation, through the skin and by ingestion.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Thioglycolic Acid across SCCS product categories, with measured dermal absorption where available.
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Danger
Pictograms
Acute ToxicityCorrosive
Hazard Class and Category
Acute Tox. 3 *; Acute Tox. 3 *; Acute Tox. 3 *; Skin Corr. 1B
Hazard Statements
- H331 Toxic if inhaled
- H311 Toxic in contact with skin
- H301 Toxic if swallowed
- H314 Causes severe skin burns and eye damage
Specific Concentration Limits / M-factors
*
Inserted via ATP: CLP00
HRIPT Human Patch Test Studies
1 human repeat insult patch test aggregated from dermatological literature.
| Test Type | N | Sensitized | Dose µg/cm² | NESIL µg/cm² | Potency |
|---|---|---|---|---|---|
| HRIPT | - | 0 | 1476.19 | - | - |
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
10,000 - 100,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
SA Saudi SFDA (III - Restricted)
Product type: (a) Hair products (b) Depilatories (c) Hair rinse-off products (d) Products intended for eyelash waving. Max: (a) (i) 8% (ii) 11% (b) 5% (c) 2% (d) 11% The abovementioned percentages are calculated as thioglycollic acid.
JPKR Japan/Korea Cosmetics
Korea (Restricted): max 8.0
Korea (Restricted): max Hair perming: 8-11% | Depilatory: 5%
BRIN Brazil/India Cosmetics
India: Restricted · max (a) (i) 8% (ii) 11% (b) 5% (c) 2% (d) 11% The abovementioned percentages are calculated as thioglycollic acid
Additional Jurisdictional Restrictions (6)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | restricted | 8 | (a) oxidative hair products (b) non-oxidative hair products (c) depilatories |
| IN | restricted | 5.0 | depilatory products |
| IN | restricted | 8.0 | hair waving rinse-off products |
| GCC | restricted | 11.0 | Hair waving/straightening products |
| BR | restricted | 8 (gen) / 11 (prof) | Hair waving/straightening products (rinse-off); Depilatories: 5%; pH 7-9.5 |
| BR | restricted | 8 (gen) / 11 (prof) | Hair waving/straightening products; pH 6-9.5 |
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
EPA Dryad Skin Absorption (physics-based)
MW: 92.11
LogP: 0.0901028
Kp epidermis: 0.02047 cm/h
% dose epidermis: 0.96%
% dose stratum corneum: 0.91%
% dose dermis: 1.04%
Source: EPA Dryad Skin Absorption 2024
Aggregated DA Values (1 records across 5 sources)
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured | 100.0% | - | - | SCCS/0167 |
Additional Ingredient Properties
1 property record from structured ingredient metadata.
hair_dye
{"cas_number": "68-11-1", "ingredient_class": "other", "chemical_class": "other", "molecular_weight_Da": "92.12", "color_result_on_hair": "Reducing agent in wave/color correction", "primary_function": "reducer", "requires_developer": "no", "sensitization_risk": "moderate", "scalp_irritation_potential": "high", "hair_damage_level": "moderate", "vegan": "yes", "typical_use_level_pct": "5-15", "cost_…
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Safety (2)
ICSC Safety Card
0915
Source: WHO/JECFA
Skin Eye Respiratory Irritation
A corrosive irritant to skin, eyes, and mucous membranes.
Source: Hazardous Substances Data Bank (HSDB)
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Depilatory
Hair waving or straightening
Reducing agent
Regulatory List Membership (1)
EU CosIng Cosmetics Ingredient Database
Expert Verdict
Expert safety assessment and concern-level summary for Thioglycolic Acid.
Regulatory Flags
potential-allergen
eu_cosing_listed
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Thioglycolic Acid by CAS number or substance name.
Studies
52
Lowest NOAEL
0.044
Highest NOAEL
1000
Units vary across source rows: mg/kg bw, mg/kg bw/d, mg/kg bw/day
SCCS Opinion
Dermal Absorption
View details ->| Absorption % | Method | Vehicle |
|---|---|---|
| 100.0% | - | - |
Known Synonyms
Acetic acid, mercapto-
4-03-00-00600
BRN 0506166
EINECS 200-677-4
Glycolic acid, thio-
Thioglycolate
Acide thioglycolique
Kyselina merkaptooctova
Kyselina thioglykolova
UNII-7857H94KHM
Mercaptoessigsaeure
Merkaptoessigsaeure
SULFANYLACETIC ACID
alpha-mercaptoacetic acid
Chemical Function
Antioxidant
Reducing agent
Depilatory
Hair waving or straightening
Regulatory Lists
fracking
Canada; pharmaceutical
fracking; water
Europe; Personal care; restricted
Personal care; Southeast Asia
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
THIOGLYCOLIC ACID
ChEMBL ID
CHEMBL116455
Max Phase
-1
Frequently Asked Questions
Is Thioglycolic Acid allowed in the EU?
Thioglycolic Acid EU regulatory status: prohibited. Maximum allowed concentration: 5.0%. This is based on EU Regulation 1223/2009 and its amendments.
What does Thioglycolic Acid do in cosmetics?
Thioglycolic Acid functions as: Depilatory, Hair Waving/Straightening, Keratolytic, Reducing Agent. It is classified as a cosmetic ingredient in our database. CAS number: 68-11-1.
What is the NOAEL for Thioglycolic Acid?
The NOAEL (No Observed Adverse Effect Level) for Thioglycolic Acid is =0.044 mg/kg bw based on a dermal absorption study via dermal route in rat. A total of 10 study endpoints are available. Source: SCCS Opinion.
Is Thioglycolic Acid used outside cosmetics?
Thioglycolic Acid also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does Thioglycolic Acid have different safety status in cosmetics vs industrial chemicals?
Thioglycolic Acid is prohibited in EU cosmetics at max 5.0% but has active industrial GHS classifications (H301, H311, H314, H317, H318, H330, H331, H312).
Compliance Tools
Check Thioglycolic Acid compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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