Get a Free 5ml Mini Now Free 5ml Mini With Every Order of The Mantle
Moumoujus

1-NAPHTHOL.

Questionable CAS 90-15-3 / HAIR DYEING

A naphthalene-derived compound primarily recognized for its role in oxidative hair coloring systems. While capable of antioxidant activity through radical scavenging, its strong sensitization potential and specialized pH requirements limit its practical applications in modern skincare formulations.

Summary

Antioxidant Hair dye precursor

Science

Mechanism of Action

Functions as a radical scavenger targeting hydroxyl and peroxyl radicals while upregulating endogenous antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GPX). However, metabolic conversion to naphthoquinone derivatives can trigger sensitization responses.

Research

Clinical Evidence

Medium confidence
Effective range 0.5–2.5%
Optimal

N/A

Key findings

  1. 01 21-month chronic dermal study at 0.5% showed no systemic toxicity in Swiss Webster mice
  2. 02 Patch testing at 2.5% demonstrated no skin irritation after 72 hours in rabbit models
  3. 03 Eye irritation studies at 2.0% revealed transient corneal opacities lasting 1-3 days

Transparency

Dusting Analysis

Not commonly dusted

Primarily used in specialized hair dye applications rather than general skincare formulations

The Formula

Formulation

Solubility
Both
Optimal pH 9 – 10
0 7 14

Stability

Exhibits extreme photosensitivity and air sensitivity leading to rapid oxidative discoloration. Requires inert gas storage conditions. Functions as weak acid with pKa 9.34.

Conflicts

  • Strong oxidizers
  • Strong bases
  • Sulfuric acid
  • Nitric acid
  • Halogens
  • Copper compounds
  • Aluminum

Safety

Safety Profile

CIR Status
Safe as used
Max tested
2%
Sensitization risk High

Classified as strong sensitizer requiring allergen warnings. SCCS restricts to 2.0% in finished products, reduced to 1.0% when combined with peroxide systems.

Our Assessment

Verdict

Questionable

Despite antioxidant properties, the high sensitization risk and demanding formulation requirements make it impractical for precision skincare applications.

Related

Similar Ingredients

Finding similar ingredients…