According to Cathy Wong, a health expert for About.com, there is no product, herb or supplement that can reverse or halt gray hair. The time for each person’s hair to begin graying is genetically programmed.
The only way to remedy gray hair is to determine if there are any abnormal causes contributing to premature gray hair. Wong states that thyroidal conditions such as Graves' disease, hyperthyroidism and Hashimoto’s disease cause premature graying. A vitamin B12 deficiency that causes anemia can also cause premature gray hair to appear, and smoking has also been linked to premature gray hair. A doctor can determine if a thyroidal condition exists, and eating foods rich in vitamin B12 and quitting smoking can help to stop premature graying.