you can never find an ingredient better than these two for dandruff, #1 Ketoconazole #2 Salicylic Acid (low concentration). Ketoconazole is a well-known ingredient used for fungal acne, which is also somehow a result of dandruff, widely available in shampoo formulations. You can go for a good 1 to 2% ketoconazole shampoo at the beginning and only when you find the product less concentration for the intensity of dandruff you have, slightly increase the dosage under a professional guidance.