Mr Kennedy and Jrob...I have been using the serum since my unit was new...and I find that the color of my hair has hardly dissapated since using...this unit is 6 months old...I bought two small bottles and I am on the last one right now...I use it everyday...with a no alcohol gel...usually after about a 3 month period I would have to color the unit... but I haven't had to do that chore as yet....So it does help maintain color as well...good stuff to say the least. Good job Jrob...cheers