Good day, First let me explain that generally premature greying of hair is a genetic phenomenon and taking too much zinc can upset your balance of other vitamins. Generally you should consume about 18 mg. of zinc per day to maintain adequate zinc intake and you can get that from foods. I looked under all the conditions zinc supplementation might benefit and their dosages and found nothing for the greying of hair. A typical Zinc Sulfate 220 mg tablet will have 50 mg zinc in it and depending on what you read, the Institute of Medicine declares a tolerable upper limit for zinc of 40 mg/d. Foods high in zinc include spinach, cashews, cocoa, pork, chicken, mung beans and mushrooms. Now if you are interested in anti-aging/regenerative therapies, that is a whole different field. I do not believe you need zinc supplements unless I were to analyze your food intake and can see a deficiency. I hope that helps you decide what to do. Regards . . .