Dr. Amy Perlmutter, of New York Dermatology Group, will often recommend that patients test out several shampoos—each one with a different active ingredient. Some will have “pyrithione zinc” while others include “selenium sulfide” or even salicylic acid, but it's smart to start with the active ingredient ketoconazole—an anti-fungal treatment that tackles the flaking, scaling and itching associated with dandruff. It's often prescribed in higher doses, but you can get this milder version over the counter.
Ketoconazole 1% shampoo,
$14.84 by Nizoral