To use this shampoo as intended—for scalp balance—apply a moderate amount directly to wet hair at the roots. Massage it into your scalp thoroughly with your fingertips (not nails) for about a minute. This massaging action helps distribute the zinc-based formula and can improve circulation. Let the lather sit on your scalp for another minute before you rinse it thoroughly, allowing the water to carry the suds through the lengths of your hair to clean them. This ensures the active ingredients have time to work where they are most needed.
Regarding frequency, it can fit well into a regular hair-washing plan. Many users with oil-prone scalps use it every time they wash their hair. However, if your scalp is sensitive or you are introducing a new active product, it may be prudent to start by using it once or twice a week, alternating with a very gentle, hydrating shampoo. Observe how your scalp feels over 2-3 weeks. The goal is a clean, comfortable scalp without over-drying or irritation. As it's a maintenance product, consistent use over time typically yields better results for controlling oiliness and flaking than occasional use. Always follow the shampoo with a conditioner applied only to the mid-lengths and ends of your hair to avoid weighing down the freshly cleansed roots.