Persistent dandruff is very common and highly treatable. If regular shampoos haven't worked, you may need a stronger medicated option. Look for shampoos containing active ingredients like Ketoconazole (an antifungal), Selenium Sulfide, Coal Tar, or Salicylic Acid to help clear the buildup. For the best results, gently massage the shampoo into your scalp and let it sit for 5 to 10 minutes before rinsing thoroughly. You can alternate between two different active ingredients if one stops being effective. If you don't see improvement after a few weeks, please consult a dermatologist, who can rule out other conditions and prescribe stronger targeted treatments.