Extra Strength Denorex dandruff shampoo and conditioner helps relieve moderate symptoms of dandruff, seborrheic dermatitis and psoriasis. Formulated with 3 percent salicylic acid, Extra Strength Denorex works to prevent the recurrence of these symptoms. The vitamin enriched shampoo and built -in conditioner provides the body and shine you would expect from a separate conditioner and the tingle tells you it’s working.