I have used Just For Men dyes for years now, from the old mixing in the bottle method to the comb-through dye. Control GX I have only been using for a few weeks now.
After a recent haircut where a lot of gray hair was exposed, I used Control GX only to notice a slight difference, compared to using the comb-through dye. On the second application of Control GX, I noticed a further difference, and believe that continued use will reduce the gray that I am so paranoid about. I am 57 by the way.
I would suggest that disposable gloves are worn as my fingernails and palms of my hands are stained.
Bottom Line: Yes, I would recommend this to a friend