For reference my hair is professionally coloured a dark brown/black. I bought this on a rec from a sales person at Trades Secrets when I was looking for shampoo and conditioner that would prolong the vibrancy of my colour. She recommended Colorglow, but the darkest shade they have is either Brown Cool or Brown Warm and nothing for shades darker, like brown-black or black. I went with Brown Warm. I use this, and the conditioner, 2-3X a week. It smells wonderful. The shampoo itself is a pearly pink colour. It lathers well, rinses easily. I would repurchase the shampoo with the conditioner. As to whether it prevents colour wash out, I donít know for sure. But once my hair is dried, straightened and ironed, it looks healthy, shiny and soft.