What is the primary ingredient in many anti-dandruff shampoos?

The primary ingredient in many anti-dandruff shampoos is often zinc pyrithione or selenium sulfide. These ingredients are specifically formulated to combat the underlying causes of dandruff, which typically include the overgrowth of a yeast-like fungus called Malassezia and scalp irritation. Zinc pyrithione works by reducing the fungi on the scalp and has antifungal properties, while selenium sulfide helps to slow down the production of skin cells and reduce itching and flaking associated with dandruff.

In contrast, salicylic acid is known for its exfoliating properties and is commonly used in treatments for scalp conditions but is not as predominant as the anti-fungal agents in managing dandruff. Caffeine, while it may have some stimulating effects on hair follicles, is not a recognized treatment for dandruff. Tea tree oil has natural antimicrobial properties and is sometimes used as a natural remedy for dandruff; however, it is not as frequently included as a primary active ingredient in traditional anti-dandruff shampoos compared to zinc pyrithione or selenium sulfide.