Start with once or twice a week, especially if your scalp is not used to tar-based cleansers. This gives you time to see how your skin responds. If your roots become oily quickly and the shampoo feels comfortable, you can gradually increase to every other day or even daily. Daily use is not a strict rule: tar shampoos are more thorough than many mild everyday cleansers, and some people only need them on wash days after heavy styling product use.
A practical pattern is to focus the shampoo on the scalp and roots, let it foam briefly, then rinse. If the lengths need conditioning, follow with a conditioner or mask applied only from mid-length to ends. Because the formula combines several surfactants and contains glycerin and allantoin, the scalp is less likely to feel tight after rinsing, but this is still not a conditioning shampoo.
If you wear hats often or use styling products regularly, you may need a deeper root cleanse more frequently. Judge the timing by how quickly the roots feel greasy rather than by a fixed schedule. Alternating this shampoo with a gentle everyday shampoo is also an option, especially during the first weeks. If your scalp becomes itchy, red, or noticeably more irritated, pause use and speak with a pharmacist or skin specialist.