Metol

Metol (CAS 55-55-0) is a photographic developing agent and oxidative hair dye intermediate, commercially available under the trade names Elon, Armol, and Genol. It carries no assigned E-code and is registered under EC number 200-237-1. The molecular formula reflects a hemi-sulfate salt form, which governs its solubility and handling characteristics.

In photographic processing, Metol acts as a primary reducing agent, donating electrons to silver halide crystals to produce a visible silver image with fine grain and high shadow detail. In oxidative hair colouring formulations, it functions as a coupler or co-developer, reacting with hydrogen peroxide and dye intermediates to generate colour within the hair cortex.

Metol is supplied as a white crystalline powder conforming to technical and cosmetic-grade specifications under REACH registration. Procurement quantities typically range from kilogram laboratory packs to multi-tonne bulk orders. Buyers should verify supplier SDS documentation for skin sensitisation classifications relevant to EU cosmetics compliance.