there is two basic types of targeting dandruff with the dandruff shampoos; one is to eliminate the scale and one is to affect the underlying cause. somebody who has very thick scale and heavy dandruff you might need both products because until you get rid of some of the scale the active ingredient won't actually reach the skin to have the proper effect. so the first products to get rid of some of this scale would be something like salicylic acid that helps loosen the scale and eliminate it from the skin. the zinc pyrithione and the selenium sulphide target the underlying yeast or fungus that can cause the dandruff to begin with. so you might need both products and you can either use them one after the other or alternate one shampoo one and the next shampoo the other. afterwards you can still use your own shampoo if you prefer. so it's a lot of shampooing but for some people who really prefer their own shampoo or don't like the way these products smell you can still use your own shampoo after and you can certainly condition afterwards as well.
how do dandruff shampoos get rid of dandruff? what's the difference between selenium sulphide and zinc pyrithione?