I have very persistent dandruff and itchy scalp and I have tried Head & Shoulders (zinc pyrithione), Nizarol (ketoconazole), and finally this. I did not get much improvement at all with H&S. Nizoral reduced dandruff the day after using it, but it really dried out my hair and scalp making it too harsh to use every day. Also, I would get dandruff again within 2 days of using Nizoral even after having used it for 2 months. Nizoral with H&S on off-days did not do the trick either. I bought this because I had not tried piroctone olamine as an anti-dandruff ingredient yet and I am happy to say that I have finally found a dandruff shampoo that actually works while being gentle enough to use every day. H&S and Nizoral tend to dry out my scalp and cause itchiness, making me scratch my scalp and causing white flakes to rain down. With this shampoo I don't feel any itchiness at all. There are still white flakes that fall down if I scratch my scalp, but they are much reduced in amount and size and I don't really have the urge to scratch any more. I think because Sebamed places great importance on gentle ingredients for the skin, this shampoo successfully combines antifungal/antidandruff power without drying the scalp.