Dandruff is a mix of oils from the hair shaft, sweat, bacteria, and scalp tissue. It is very thick and oily in your hair. If you have white flakes on your shirt, then you DO NOT have dandruff… your scalp is just dry! Many dandruff shampoos either use zinc pyrithione or tea tree oil.
Zinc pyrithione is the active ingredient in many anti-dandruff shampoos. It has both anti fungal and antibacterial properties. Two popular over the counter dandruff shampoos are Head & Shoulders and Selsun Blue.
Tea tree oil has antibacterial, anti fungal, and antiseptic qualities. It is a natural oil coming from the leaves of a native plant in New South Wales, Australia. Tea tree shampoos use a natural ingredient to treat dandruff. There are many tea tree shampoos, one popular tea tree shampoo is by Paul Mitchell. Their shampoos are safe for color treated hair.