Alternating between Kerastase Bain Vital Haute Tolerance (For sensitive scalp - looks like you have dandruff but your skin is reddish) and their new range Biotin (can't remember the name). It works so far since I had many difficulties in getting a decent shampoo that doesn't irritate my scalp. I believe if hair is not healthy means scalp is not properly taken care of (diet is important too!). If you have sensitive scalp and coloured hair, you can alternate between shampoos.