Added oil in Garnier Olia 4.0 Dark Brown Hair Dye maximises the colour result, leaving hair smooth and glossy. Garnier Olia 4. 0 Dark Brown Hair Dye is an ammonia free formula and powered by 60% oils. The hair colour visibly improves the quality of hair, for better shine and 35% smoother hair. Olia home hair colour will also pr maximum colour performance for lavish, vivid and long-lasting colour. Plus, a unique sensorial application and optimal scalp comfort with our non-drip smooth velvety texture of the colourant cream.