1-Naphthol
INCI: 1-NAPHTHOL
Regulatory Status
For full compliance data across 55 jurisdictions, use the Substance Compliance tool.
Safety Data
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
6 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 |
| LOAEL | 100 mg/kg bw/day | oral | rat | Developmental | COSMOS_DB |
| NOAEL | ca.130 mg/kg bw/day | oral | rat | oral | REACH |
| NOAEL | ca.0.5 other | dermal | code:3484 | dermal | REACH |
| NOAEL | ca.100 mg/kg bw/day | oral | mouse | oral | REACH |
| NOAEL | ca.120 mg/kg bw/day | oral | rat | oral | REACH |
Safety Opinions
Official safety assessments from the Scientific Committee on Consumer Safety (SCCS) and Cosmetic Ingredient Review (CIR).
Sensitization Profile
Contact sensitization data for 1-Naphthol based on clinical patch test studies and IFRA standards.
Source: IVDK; NACDG; ESSCA
Expert Verdict
Skin/eye irritant; sensitizer; restricted to oxidative hair dye only; mandatory consumer warning on label ("Can cause an allergic reaction"); do not use on eyebrows/eyelashes; not for use in other cosmetic product types
Regulatory Flags
Frequently Asked Questions
Is 1-Naphthol safe in cosmetics?
Skin/eye irritant; sensitizer; restricted to oxidative hair dye only; mandatory consumer warning on label ("Can cause an allergic reaction"); do not use on eyebrows/eyelashes; not for use in other cosmetic product types The EU classifies 1-Naphthol as "restricted". Safety rating: MODERATE. 6 toxicological study endpoint(s) are available in our database. This ingredient has been reviewed by cir.
Is 1-Naphthol allowed in the EU?
1-Naphthol EU regulatory status: restricted. Maximum allowed concentration: 2.0%. This is based on EU Regulation 1223/2009 and its amendments.
What does 1-Naphthol do in cosmetics?
1-Naphthol functions as: Oxidative hair dye intermediate (coupler). It is classified as a cosmetic ingredient in our database. CAS number: 90-15-3.
What is the Margin of Safety for 1-Naphthol?
adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.
What is the NOAEL for 1-Naphthol?
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 6 study endpoints are available. Source: COSMOS_DB.
Compliance Tools
Check 1-Naphthol compliance across multiple jurisdictions:
Related Ingredients
Is 1-Naphthol in Your Products?
Scan any product label with Piro — our free ingredient scanner. Point your camera at the ingredients list and get instant safety scores for every ingredient.
Try Piro Free →Analyze Your Full Ingredient List
Paste any INCI list into the Decoder for instant safety analysis, or calculate the Margin of Safety for 1-Naphthol in your formulation.