Is 4-Amino-2-Hydroxytoluene safe in cosmetics?
4-Amino-2-Hydroxytoluene has a safety rating of "MODERATE" in our database. EU status: prohibited. US status: permitted. 4 toxicological study endpoint(s) are available in our database.
4-Amino-2-Hydroxytoluene
Also known as: Phenol, 4-amino-3-methyl-, BRN 2078803, EINECS 220-621-2, NSC 72170, UNII-12R07I1K8C (+11 more)
INCI: 4-AMINO-2-HYDROXYTOLUENE
4-Amino-2-Hydroxytoluene (CAS 2835-99-6) is a cosmetic cosmetic ingredient functioning as Hair dyeing (oxidative hair dye coupler). Reported NOAEL =60 mg/kg in rat (SCCS_vision_codex); EU Regulation 1223/2009 status: prohibited. 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 2835-99-6 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
4-Amino-2-Hydroxytoluene is prohibited in EU cosmetics but has active industrial GHS classifications (H302, H315, H317, H319, H335, H400, H410).
Source: Cosmetics: ingredients.eu_status; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Hair dyeing (oxidative hair dye coupler)
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
4-amino-3-methylphenol
InChIKey
QGNGOGOOPUYKMC-UHFFFAOYSA-N
Regulatory Status
EU EU Status
prohibited
US US Status
permitted
US Notes
Permitted under coal tar hair dye exemption (21 USC §361(a)); CIR concluded safe for use as a hair dye ingredient at current practices of use and concentration
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for 4-Amino-2-Hydroxytoluene.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
4 study endpoints found for 4-Amino-2-Hydroxytoluene. 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 | =60 mg/kg | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =60 mg/kg | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =60 mg/kg | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =60 mg/kg | oral | rat | repeated dose toxicity | SCCS_vision_codex |
Sensitization Profile
Contact sensitization data for 4-Amino-2-Hydroxytoluene based on clinical patch test studies and IFRA standards.
Sensitization Rate
low
Allergen Class
dye
EU Allergen Listed
no
Patch Test Positive Rate
0.5%
Cross-reactivity Group
para-amino-group
Reaction Type
contact-dermatitis
Source: IVDK; NACDG; ESSCA
Sensitization AOP Dashboard
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
DPRA Cys %
74.14%
DPRA Lys %
28.44%
KeratinoSens IC50
67.648 µM
hCLAT CV75
22.7 µg/mL
LLNA EC3
1.8%
NESIL
450 µg/cm²
LLNA: Strong (1A)
GHS: 1A
Source: LLNA: Scientific Committee for Consumer Products (SCCP). Opinion on 4-amino-m-cresol. 2005 Sep 20. COUP A No.: A74; SCCP/0898/05. | Kern et al. (2010); DPRA: Cosmetics Europe | Urbisch et al. 2015 [DOI:10.1016/j.yrtph.2014.12.008]; KS: Cosmetics Europe | Urbisch et al. 2015 [DOI:10.1016/j.yrtph.2014.12.008]; hCLAT: Cosmetics Europe
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
10 - 100 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
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.
KR Korea MFDS Annex 2 (Restricted)
Category: Restricted. Max: 산화염모제에 1.5%. 기타 제품에는 사용금지
SA Saudi SFDA (III - Restricted)
Product type: (a) Hair dye substance in oxidative hair dye products (b) Products intended for colouring eyelashes.
BRIN Brazil/India Cosmetics
India: Restricted
Additional Jurisdictional Restrictions (4)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | banned | - | - |
| CN | permitted_hair_dye | 1 | Oxidative hair dye products |
| CN | permitted_hair_dye | 1 | Oxidative hair dye products |
| BR | permitted_hair_dye | - | Oxidative hair dye (4-amino-m-cresol) |
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Aggregated DA Values (1 records across 5 sources)
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured_sccs_opinion | 2.73% | - | - | SCCP/0898 |
Additional Ingredient Properties
2 property records from structured ingredient metadata.
allergen_detail
{"eu_allergen_listed": "no", "allergen_class": "dye", "cross_reactivity_group": "para-amino-group", "patch_test_frequency_pct": "0.5", "sensitization_rate": "low", "common_reaction_type": "contact-dermatitis", "ifra_restricted": "no", "source": "IVDK; NACDG; ESSCA"}
hair_dye
{"cas_number": "2835-95-2", "ingredient_class": "oxidative_dye_precursor", "chemical_class": "para_aminophenol", "molecular_weight_Da": "123.15", "color_result_on_hair": "Red-brown", "shade_range": "red", "primary_function": "precursor", "oxidative_dye_type": "primary_intermediate", "requires_developer": "yes", "permanence": "permanent", "oxidation_mechanism": "coupling", "coupling_position": "par…
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Dye
Regulatory List Membership (1)
EU CosIng Cosmetics Ingredient Database
Expert Verdict
Expert safety assessment and concern-level summary for 4-Amino-2-Hydroxytoluene.
Regulatory Flags
eu_cosing_listed
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to 4-Amino-2-Hydroxytoluene by CAS number or substance name.
Studies
4
Lowest NOAEL
60 mg/kg
Highest NOAEL
60 mg/kg
SCCS_vision_codex
Dermal Absorption
View details ->| Absorption % | Method | Vehicle |
|---|---|---|
| 2.73% | SCCS opinion extraction | - |
Known Synonyms
Phenol, 4-amino-3-methyl-
BRN 2078803
EINECS 220-621-2
NSC 72170
UNII-12R07I1K8C
2-Amino-5-hydroxytoluene
2-Methyl-4-hydroxyaniline
3-Methyl-4-aminophenol
4-Amino-3-methylphenol
4-Hydroxy-2-methylaniline
4-Hydroxy-o-toluidine
4-OH-6'-methylalanine
4-hydroxy-6'-methylalanine
p-Amino-m-cresol
p-Hydroxy-o-toluidine
4-hydroxy-6-methylaniline
Chemical Function
Dye
Regulatory Lists
Europe; Personal care; restricted
Canada; Personal care; Substances in PCP - Canada (4/2014)
Europe; Personal care - hair coloring
Europe; Personal care - hair coloring
Europe; Personal care - hair coloring
Europe; Personal care - hair coloring
Australian Status
AICIS status: listed
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.
ChEMBL ID
CHEMBL3092390
Frequently Asked Questions
Is 4-Amino-2-Hydroxytoluene allowed in the EU?
4-Amino-2-Hydroxytoluene EU regulatory status: prohibited. This is based on EU Regulation 1223/2009 and its amendments.
What does 4-Amino-2-Hydroxytoluene do in cosmetics?
4-Amino-2-Hydroxytoluene functions as: Hair dyeing (oxidative hair dye coupler). It is classified as a cosmetic ingredient in our database. CAS number: 2835-99-6.
What is the NOAEL for 4-Amino-2-Hydroxytoluene?
The NOAEL (No Observed Adverse Effect Level) for 4-Amino-2-Hydroxytoluene is =60 mg/kg based on a repeated dose toxicity study via oral route in rat. A total of 4 study endpoints are available. Source: SCCS_vision_codex.
Is 4-Amino-2-Hydroxytoluene used outside cosmetics?
4-Amino-2-Hydroxytoluene 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 4-Amino-2-Hydroxytoluene have different safety status in cosmetics vs industrial chemicals?
4-Amino-2-Hydroxytoluene is prohibited in EU cosmetics but has active industrial GHS classifications (H302, H315, H317, H319, H335, H400, H410).
Compliance Tools
Check 4-Amino-2-Hydroxytoluene compliance across multiple jurisdictions:
Ingredient Decoder
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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
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