1-Naphthol
1-Naphthol is an organic compound used as a color coupler in permanent hair dyes. It reacts with other dye intermediates to create various shades, particularly red and violet tones. It is not used directly for its own color but as a component in the dyeing process.
Hair dye intermediateVegan
RiskHigh 2.5 / 4
Sensitization i2.5 / 4
Risk of allergic contact dermatitis or immune-based reactions. Fragrance allergens, preservatives, botanicals, and some dyes may score here.
Irritation i2 / 4
Risk of short-term irritation — stinging, burning, dryness, redness, or discomfort. Common for strong actives, acids, retinoids, fragrances, and harsh surfactants.
Systemic exposure i1 / 4
Whether it has meaningful potential to be absorbed into the body at levels that may matter biologically. Most cosmetic ingredients score low unless there is known concern or high exposure.
Rated by SpottyLabs' ingredient methodology, independent of brands.
Things to watch
- potential skin sensitizer
- possible irritant
See how this matches your skin
Find out exactly what you put onto your skin. Scan any product before you buy. Free and independent — no brand is paying us. Available on Android and iOS.
Frequently asked questions
- What is 1-Naphthol used for in hair dye?
- 1-Naphthol acts as a color coupler in permanent hair dyes, reacting with other ingredients to form the final hair color, often contributing to red and violet shades.
- Is 1-Naphthol safe to use?
- 1-Naphthol is considered safe for use in hair dyes within regulatory limits, but it can be a skin sensitizer and irritant for some individuals, requiring patch testing before use.
