I am really happy not only with that particular product, but with all the ones in the range. I cannot honestly say from when the effect is noticed, although I can say that I noticed it before I ran out of the first 150ml bottle. Now, I have always used all 3 products at the same time: shampoo, conditioner, and the scalp treatment. Notes: If you notice that the shampoo makes you little lather, rub it on your hands before applying. The conditioner: use suuuuuper a little and put it only on the scalp (I scratch), for the rest, use the conditioner you want, the one you like the most! After showering and with wet hair I put on the treatment. Me: I make the middle part and I put on the foam. If I do it with dry hair, it looks dirty. Then I put the oil on the rest of my hair. I hope I have been helpful!!!