Is 1,5-Naphthalenediol safe in cosmetics?
1,5-Naphthalenediol 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.
1,5-Naphthalenediol
Also known as: Naphthalene-1,5-diol, 4-06-00-06554, BRN 2044951, 1,5-Dihydroxynapthalene, EINECS 201-487-4 (+1 more)
INCI: 1,5-NAPHTHALENEDIOL
1,5-Naphthalenediol (CAS 83-56-7) is a cosmetic cosmetic ingredient functioning as Hair dye precursor/coupler — reacts with primary intermediates under oxidative. NOAEL 50 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: prohibited, max 1.0%. 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 83-56-7 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
1,5-Naphthalenediol is prohibited in EU cosmetics at max 1.0% but has active industrial GHS classifications (H302, H317, H319, H411).
Source: Cosmetics: ingredients.eu_status/eu_max; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Hair dye precursor/coupler — reacts with primary intermediates under oxidative conditions to form final dye
Safety Rating
MODERATE
Regulatory Status
EU EU Status
prohibited
EU Max Conc.
1.0%
US US Status
permitted
US Notes
Permitted under coal tar hair dye exemption (21 CFR 73/74); subject to FDA caution labeling requirements
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for 1,5-Naphthalenediol.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for 1,5-Naphthalenediol. 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 | =0.02 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.02 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.02 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.02 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =50 mg/kg/day | - | - | genotoxicity | SCCS_vision_codex |
| NOAEL | =50 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =50 mg/kg bw/day | - | - | genotoxicity | SCCS_vision_codex |
| NOAEL | =50 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =50 mg/kg/day | - | - | genotoxicity | SCCS_vision_codex |
| NOAEL | =50 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCS_vision_codex |
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 mildly irritating to the eyes.
Routes of Exposure
The substance can be absorbed into the body by ingestion.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for 1,5-Naphthalenediol 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 Lys %
0%
KeratinoSens IC50
89.774 µM
hCLAT CV75
64.6 µg/mL
LLNA EC3
3.4%
NESIL
850 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
1 - 10 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.
SA Saudi SFDA (III - Restricted)
Product type: a) Hair dye substance in oxidative hair dye products b) Hair dye substance in non-oxidative hair dye products. Max: b) 1.0%.
BRIN Brazil/India Cosmetics
India: Restricted · max b) 1.0%
Additional Ingredient Properties
1 property record from structured ingredient metadata.
hair_dye
{"cas_number": "83-56-7", "ingredient_class": "oxidative_dye_coupler", "chemical_class": "naphtol", "molecular_weight_Da": "160.17", "color_result_on_hair": "Purple modifier", "shade_range": "fashion_color", "primary_function": "coupler", "oxidative_dye_type": "coupler", "requires_developer": "yes", "permanence": "permanent", "oxidation_mechanism": "coupling", "hair_penetration_depth": "cortex", "…
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 1,5-Naphthalenediol.
Regulatory Flags
eu_cosing_listed
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to 1,5-Naphthalenediol by CAS number or substance name.
Studies
29
Lowest NOAEL
0.02
Highest NOAEL
360
Units vary across source rows: mg/kg bw/day, mg/kg/day, mg/kg bw/d
ToxValDB_ECHA_IUCLID
SCCS_vision_codex
Known Synonyms
Naphthalene-1,5-diol
4-06-00-06554
BRN 2044951
1,5-Dihydroxynapthalene
EINECS 201-487-4
UNII-P25HC23VH6
Chemical Function
Dye
Regulatory Lists
Europe; Personal care - hair coloring
Europe; Personal care; restricted
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
CHEMBL204658
Frequently Asked Questions
Is 1,5-Naphthalenediol allowed in the EU?
1,5-Naphthalenediol EU regulatory status: prohibited. Maximum allowed concentration: 1.0%. This is based on EU Regulation 1223/2009 and its amendments.
What does 1,5-Naphthalenediol do in cosmetics?
1,5-Naphthalenediol functions as: Hair dye precursor/coupler — reacts with primary intermediates under oxidative conditions to form final dye. It is classified as a cosmetic ingredient in our database. CAS number: 83-56-7.
What is the NOAEL for 1,5-Naphthalenediol?
The NOAEL (No Observed Adverse Effect Level) for 1,5-Naphthalenediol is =0.02 mg/kg bw/d based on a dermal absorption study via oral route in rat. A total of 10 study endpoints are available. Source: SCCS_vision_codex.
Is 1,5-Naphthalenediol used outside cosmetics?
1,5-Naphthalenediol 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 1,5-Naphthalenediol have different safety status in cosmetics vs industrial chemicals?
1,5-Naphthalenediol is prohibited in EU cosmetics at max 1.0% but has active industrial GHS classifications (H302, H317, H319, H411).
Compliance Tools
Check 1,5-Naphthalenediol 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
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