The answer is no. There is no basis for the widespread idea that hair and scalp eventually develop a tolerance to the active ingredients in anti-dandruff shampoos.
In 50 years of research, there has never been any evidence to support the claim that one can acquire immunity to the zinc pyrithione in our anti-dandruff shampoos.
Head & Shoulders experts even tried to verify if this claim had any basis by conducting a 12-month clinical trial over all four seasons.
Throughout the study, it was found that Head & Shoulders shampoo users had less scalp flaking than those using a regular shampoo (the "placebo"). And the effectiveness of Head & Shoulders shampoo was the same in the last month of the test as in the first.
So use Head & Shoulders continuously and you will no longer fear dandruff.