I currently have a full head of foils, but a massive regrowth of my natural hair colour brown. Can I dye my hair brown or will it ruin my hair?
Colouring it brown shouldn't ruin your hair. As long as you use the correct products and ideally have it done at a professional salon. If the hair is very light blonde then you will need to have it pre-coloured to balance out the colour before a shade close to your natural is applied over the top.
John Clark at Brooks+Brooks, London