100% pure, fairly traded organic Indigo Black herbal hair dye, made in the UK. A non-invasive plant colour that gently coats the hair shaft to naturally darken brown hair towards black, add glossy natural colour and increased volume. Colour develops in 0.5 to 4 hours and typically lasts around 3 to 4 weeks on roots. Free from synthetic chemicals, PPD and ammonia. Key benefits: Gives glossy, natural-looking colour and increased volume (maximise leave-in time for deeper shade) Conditions and strengthens hair, leaving a healthy shine 100% certified organic indigo, fairly traded and chemical-free Indigo Black works by semi-transparently coating your hair shaft; the final shade depends on your existing hair colour and porosity. It may darken brown hair to a darker brown or black; lighter or grey hair must first be coloured red or brown before applying Indigo Black, otherwise an unattractive bluish tint can occur. Leave-in time of 0.5 to 4 hours determines depth of colour; longer or repeated applications give darker results. Colour longevity averages 3 to 4 weeks on roots but can become more persistent on porous, weathered lengths. Remove product build-up with a clarifying shampoo before use and always strand test a root-to-tip section to check outcome. Colour deepens over hours and days as it oxidises. Chemical lightening affects results and bleaching after indigo use is not recommended unless the dye has faded or grown out; if attempting bleach, strand test first. For a natural darkening option, choose Indigo Black from Holland Barrett; follow in-box instructions and strand test guidance to achieve the best, safest results.