First you have to decide if you have dry scalp or dandruff. This isn't always easy to do because both result in visible flakes on the scalp, but each condition usually requires a different approach. You may even have both.
Dry scalp, just like dry skin elsewhere on your body, is simply the result of insufficient sebum (natural skin oils) production. It usually causes small, white flakes and accompanies dry-looking hair. Dandruff isn't related to your skin type, but caused when both the scalp microbiome and sebum production are unbalanced. It usually produces larger, yellowish flakes from an overactive production of skin cells.
DERCOS Anti-Dandruff DS Shampoo for Dry Hair targets both dry scalp and dandruff, rebalancing scalp microbiome and sebum production after just four weeks of use.[1] It eliminates up to 100% dandruff from first use [2] and provides +6 weeks anti relapse.[3]