I have found it makes my dandruff problem ALOT worse when I take it. Possibly because of the reduced sebum secretion due to the DHT-blocking effects of the Nizoral. It may make your skin dryer than usual. Keep in mind Nizoral is mainly made for use on the scalp, though it does work elsewhere.
I like to keep it in my hair for about 2 or 3 minutes in the shower before I wash it out.