Also known as: 1-naphthalenol, NAPHTHOL, CI Oxidation Base 33, EINECS 201-969-4, UNII-2A71EAQ389 (+6 more)
INCI: 1-NAPHTHOL
1-Naphthol (CAS 90-15-3) is a cosmetic cosmetic ingredient functioning as Oxidative hair dye intermediate (coupler). NOAEL 120 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max 2.0%; 1 safety opinion reviewed (CIR Safety Assessment). Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
1-Naphthol is classified GHS Danger (H302, H311, H312, H315, H317, H318, H335, H400) in the chemicals database but is restricted in EU cosmetics at max 2.0%.
Source: Cosmetics: ingredients.eu status/eu max; Chemicals: ghs classifications.signal word/hazard statement code
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Margin of Safety, dermal absorption, and sensitization profile summaries for 1-Naphthol.
Calculate MoS for your specific formulation with the MoS Calculator.
10 study endpoints found for 1-Naphthol. 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 | 20 mg/kg bw/day | oral | rat | Developmental | COSMOS DB |
| NOAEL | =20 mg/kg bw/day | - | rat | developmental toxicity | SCCNFP Opinion |
| NOAEL | =20 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =20 mg/kg bw/day | - | rat | developmental toxicity | SCCNFP Opinion |
| NOAEL | =20 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =20 mg/kg bw/day | - | rat | developmental toxicity | SCCNFP Opinion |
| NOAEL | =20 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =20 mg/kg bw/day | - | rat | developmental toxicity | SCCNFP Opinion |
| NOAEL | =20 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =100 mg/kg bw/day | - | rat | developmental toxicity | SCCNFP Opinion |
Official safety assessments from the Scientific Committee on Consumer Safety (SCCS) and Cosmetic Ingredient Review (CIR).
Pre-calculated NOAEL → SED → MoS audit trail for 1-Naphthol across SCCS product categories, with measured dermal absorption where available.
Contact sensitization data for 1-Naphthol based on clinical patch test studies and IFRA standards.
Source: IVDK; NACDG; ESSCA
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Inserted via ATP: CLP00
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
Source: LLNA: Gerberick et al. (2005); DPRA: Nukada et al. 2013 [DOI:10.1016/j.tiv.2012.11.006] | Natsch et al. 2013 [DOI:10.1002/jat.2868]; KS: Urbisch et al. 2015 [DOI:10.1016/j.yrtph.2014.12.008] | Natsch et al. 2013 [DOI:10.1002/jat.2868]; hCLAT: Ashikaga et al. 2010 [DOI:10.1177/026119291003800403]
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | permitted_hair_dye | 2 | Oxidative hair dye products |
| BR | restricted | 2 | Oxidative hair dyes only; when combined with H2O2 max 1% in ready-to-use product |
| BR | permitted_hair_dye | 2 | Oxidative hair dye; max 1% in ready-to-use with H2O2 |
| ASEAN | restricted | 2% | Oxidative hair dyes |
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Source: Roberts Cheruvu Mendeley 2022
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured | 4.0% | in_vitro | - | SCCP/0125 |
| measured | 2.0% | - | - | SCCP/0125 |
| measured | 65.0% | - | - | SCCP/0125 |
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Preliminary editorial summary for 1-Naphthol — not a computed safety verdict. See the sourced toxicological data above.
Public NOAEL study rows linked to 1-Naphthol by CAS number or substance name.
Units vary across source rows: mg/kg bw/day, mg/kg bw, mg/kg
| Absorption % | Method | Vehicle |
|---|---|---|
| 4.0% | in_vitro | - |
| 2.0% | - | - |
| 65.0% | - | - |
Same-CAS public records found in pharmaceutical data.
Same-CAS rows from the pharmaceutical spoke database.
1-Naphthol 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. This ingredient has been reviewed by CIR Safety Assessment.
1-Naphthol EU regulatory status: restricted. Maximum allowed concentration: 2.0%. This is based on EU Regulation 1223/2009 and its amendments.
1-Naphthol functions as: Oxidative hair dye intermediate (coupler). It is classified as a cosmetic ingredient in our database. CAS number: 90-15-3.
The NOAEL (No Observed Adverse Effect Level) for 1-Naphthol is 20 mg/kg bw/day based on a Developmental study via oral route in rat. A total of 10 study endpoints are available. Source: COSMOS DB.
1-Naphthol 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.
1-Naphthol is classified GHS Danger (H302, H311, H312, H315, H317, H318, H335, H400) in the chemicals database but is restricted in EU cosmetics at max 2.0%.
Check 1-Naphthol compliance across multiple jurisdictions:
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