Hair colourant: can I apply on hair having previously used Henna or colouring products with metal salts?
No, applying Garnier hair colorant to hair previously exposed to Henna or metal-salt hair treatment is not recommended. The hair’s structure could become brittle.
It is, nevertheless, recommended to wait for the Henna or metal-salt hair treatment before applying Garnier hair colouring.
Garnier hair colouring will nourish and treat hair that has previously been coloured and, as a result, that is dry.