2-Amino-6-Chloro-4-Nitrophenol

FunctionNitro hair dye (restricted-use)

What it is — 2-Amino-6-Chloro-4-Nitrophenol is a nitro-type direct hair dye. Nitro dyes sit between basic dyes and oxidative dyes: like basic dyes they arrive pre-formed and need no peroxide, but their smaller molecules penetrate a little further into the strand, so the tone holds longer than a purely surface deposit.

What it does — It supplies a red-brown to burgundy note in a shade blend. In grey-covering shampoos it is typically paired with basic dyes, adding depth and staying power that cationic dyes alone cannot reach.

Typical use — Semi-permanent and gradual hair colour, including grey-toning shampoos and treatments. In Korea it appears on the 식약처 list of ingredients that may not be used in cosmetics generally, but is permitted in hair colour products at up to 2.0%. The EU applies a comparable hair-dye-only restriction. Regulators single these dyes out not because a compliant product is unsafe, but because concentration and product type both have to be controlled.

Who it suits / good to know — It avoids the PPD-class chemistry behind most hair-dye allergy, and a product using it is genuinely gentler than a permanent oxidative dye. It is still a dye applied to the scalp, and staining of skin and nails during use is normal. Colour builds over repeated use rather than covering in one wash.

Safety — DHALIORA grades it mid risk: a restricted-use hair colourant, permitted only within a concentration cap, with a much lower sensitisation profile than oxidative dyes. This reflects the ingredient in general and is not medical advice; patch-test if your scalp is easily irritated.