Natural Remedies for Gray Hair

500mg Ashwagandha with breaky and dinner 5-6 days a week, and I might add not for grey hair, was taken for about a year. Hubby was about 10% grey but not now - no grey. We did not notice it till about 6 months. Has not had any for 6 months and still no grey. He was also taking neem and tulsi for 3-4 weeks on and off and zinc. The zinc was taken only once or twice a week. This is the second time he has got rid of his grey hair without trying, The first time he was young to be going grey.