I firstly need to mention that I only used this conditioner in Mahogany colour once as I had a reaction to the product. BUT, although I had to wash the conditioner off almost immediately after massaging through my hair, I was amazed at (a) the change to a beautiful colour in my hair; and (b) how long the colour actually lasted on my previously colour-treated hair. Most of my colour is now grown or washed out, and even the natural & grey colour at the top half of my hair became beautifully coloured by this product. The bottom half of my hair took on the mahogany colour very well and lasted for more than 4 weeks, but it did wash out within 2-3 shampoos on the non-coloured top half of my hair. So I can honestly say that this product DOES WORK to keep your coloured hair looking freshly coloured :) An awesome product overall!