If you just want to cover the grey to match your natural colour then you would use a very dark brown or a black permanent tint, depending on your preference. These shades do minimal damage as they would be used with a 10 volume developer, which only deposits colour and doesn’t really lift. This method will last longer but you will get visible growth within 2-3 weeks. The alternative is to use a colour shampoo, also known as a demi-permanent colour. This won’t damage your hair but it will fade with each wash and may or may not cover the grey as effectively as a permanent tint.