Since regular shampoos haven't worked for three years, you likely have a common scalp condition called seborrheic dermatitis. I recommend trying an over-the-counter medicated shampoo containing active ingredients like ketoconazole, selenium sulfide, or zinc pyrithione. If you have thick flakes, a salicylic acid shampoo can help exfoliate the scalp.\n\nTo use it effectively, massage the shampoo into your scalp and let it sit for 5 to 10 minutes before rinsing thoroughly. Use this 2 to 3 times a week. If you don't see improvement within a month, please consult a dermatologist, who can prescribe stronger treatments like topical corticosteroids. Rest assured, this is highly treatable and very common.