Dandruff is tricky because it can be caused by more than one thing. What you think is dandruff may be dry scalp—you can tell the difference because the skin on your head feel itchy and flakes are small and dry, not big or greasy. If you've always used shampoo and conditioner for oily hair, or have avoided conditioner completely because you think your hair is oily, you may be overstripping your scalp and making it dry. Try switching to a normal hair or even dry hair shampoo and see if the problem rights itself.
In the case of regular dandruff, there are a couple of ways to go, and they both work—for some people. In one case is the dandruff that's related to an excess of an otherwise normal bacteria. Anti-fungal or anti-bacterial shampoos, used on a regular basis can reduce the numbers of the bacteria, which seem to increase to the scalp's natural oil (sebum) production, resulting in an abnormally oily scalp. All scalps, like all skin, shed skin cells daily, but an oily scalp can make them clump together and shed in greater numbers. Getting rid of some of the bacteria reduces the oil production and lessens the shedding, eliminating dandruff. Although there are lots of touted remedies, the best way to control dandruff is by using the right shampoo on a regular basis. And keep using it: dandruff comes back if you don't keep using the shampoo.
There are lots of anti-dandruff shampoos on the market, and some work better than others depending on who you are. Some brands have an active ingredient like salicylic acid, which is the main ingredient in aspirin; others use zinc or sulfur, both of which have also been used in other skin related ailments such as acne or dermatitis. Some people do just fine with a natural shampoo whose main ingredient is tea tree oil, a natural anti-fungal and antibiotic, but others prefer other brands because they can't stand the distinctive tea-tree scent. Start with the local supermarket brand of dandruff shampoo, which probably has the same formula as the more expensive brands, and once you find a shampoo that works for you, stick with it. Sometimes it's just a matter of using the right shampoo several times a week or every day.
