Is 2,4-Diaminophenoxyethanol HCl safe in cosmetics?
2,4-Diaminophenoxyethanol HCl has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
2,4-Diaminophenoxyethanol HCl
INCI: 2,4-DIAMINOPHENOXYETHANOL HCL
2,4-Diaminophenoxyethanol HCl (CAS 66422-95-5) is a cosmetic cosmetic ingredient functioning as Oxidative hair dye (primary intermediate/coupler). NOAEL 20 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max 2.0%. Industrial safety data is also available in the chemical safety database.
View industrial chemical safety profile for CAS 66422-95-5 →
Auto-generated CPSR Part A draft with source citations
Function
Oxidative hair dye (primary intermediate/coupler)
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
2-(2,4-diaminophenoxy)ethanol;hydrochloride
InChIKey
PBVFDMZFBPZIMC-UHFFFAOYSA-N
Regulatory Status
EU EU Status
restricted
EU Max Conc.
2.0%
US US Status
permitted
US Notes
CIR: Safe as a cosmetic ingredient in hair dyes as practiced
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for 2,4-Diaminophenoxyethanol HCl.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for 2,4-Diaminophenoxyethanol HCl. 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 | 4 mg/kg bw/day | oral | rat | Subchronic | COSMOS_DB |
| NOAEL | 20 mg/kg bw/day | oral | rat | Developmental | COSMOS_DB |
| NOAEL | =0.051 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
| NOAEL | =0.051 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
| NOAEL | =0.051 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
| NOAEL | =0.051 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
| NOAEL | =20 mg/kg/day | - | - | NOAEL study | SCCS_vision_codex |
| NOAEL | =20 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
| NOAEL | =20 mg/kg/day | - | - | NOAEL study | SCCS_vision_codex |
| NOAEL | =20 mg/kg | oral | rat | developmental toxicity | SCCS_vision_codex |
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for 2,4-Diaminophenoxyethanol HCl across SCCS product categories, with measured dermal absorption where available.
Sensitization AOP Dashboard
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
DPRA Cys %
100%
DPRA Lys %
12.9%
KeratinoSens IC50
1578.217 µM
hCLAT CV75
831.8 µg/mL
LLNA EC3
3.2%
NESIL
800 µg/cm²
LLNA: Moderate (1B)
GHS: 1B
Source: LLNA: CosmEur database; DPRA: Cosmetics Europe; KS: Cosmetics Europe; hCLAT: Cosmetics Europe
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
100 - 1,000 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 0.5%. 기타 제품에는 사용금지
Additional Jurisdictional Restrictions (1)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| BR | permitted_hair_dye | - | Oxidative hair dye |
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Aggregated DA Values (3 records across 5 sources)
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured | 94.0% | - | - | SCCP/0042 |
| measured | 0.26% | - | - | SCCP/0042 |
| measured | 1.23% | - | - | SCCP/0042 |
Additional Ingredient Properties
1 property record from structured ingredient metadata.
hair_dye
{"cas_number": "66422-95-5", "ingredient_class": "oxidative_dye_coupler", "chemical_class": "other", "molecular_weight_Da": "204.65", "color_result_on_hair": "Red-orange modifier", "shade_range": "red", "primary_function": "coupler", "oxidative_dye_type": "coupler", "requires_developer": "yes", "permanence": "permanent", "oxidation_mechanism": "coupling", "hair_penetration_depth": "cortex", "sensi…
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Dye
Expert Verdict
Expert safety assessment and concern-level summary for 2,4-Diaminophenoxyethanol HCl.
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to 2,4-Diaminophenoxyethanol HCl by CAS number or substance name.
Studies
15
Lowest NOAEL
0.051
Highest NOAEL
20
Units vary across source rows: mg/kg bw/day, mg/kg/day, mg/kg
COSMOS_DB
ToxValDB_ECHA_IUCLID
SCCS_vision_codex
Dermal Absorption
View details ->| Absorption % | Method | Vehicle |
|---|---|---|
| 94.0% | - | - |
| 0.26% | - | - |
| 1.23% | - | - |
Chemical Function
Dye
Regulatory Lists
Europe; Personal care - hair coloring
detected; Europe; Personal care - hair coloring - hair color - professional
detected; Europe; Personal care - hair coloring
detected; Europe; Personal care - hair coloring
detected; Europe; Personal care - hair coloring
Danish Environmental Protection Agency
Danish Environmental Protection Agency
Australian Status
AICIS status: listed
Frequently Asked Questions
Is 2,4-Diaminophenoxyethanol HCl allowed in the EU?
2,4-Diaminophenoxyethanol HCl EU regulatory status: restricted. Maximum allowed concentration: 2.0%. This is based on EU Regulation 1223/2009 and its amendments.
What does 2,4-Diaminophenoxyethanol HCl do in cosmetics?
2,4-Diaminophenoxyethanol HCl functions as: Oxidative hair dye (primary intermediate/coupler). It is classified as a cosmetic ingredient in our database. CAS number: 66422-95-5.
What is the NOAEL for 2,4-Diaminophenoxyethanol HCl?
The NOAEL (No Observed Adverse Effect Level) for 2,4-Diaminophenoxyethanol HCl is 4 mg/kg bw/day based on a Subchronic study via oral route in rat. A total of 10 study endpoints are available. Source: COSMOS_DB.
Compliance Tools
Check 2,4-Diaminophenoxyethanol HCl compliance across multiple jurisdictions:
Ingredient Decoder
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82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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