Blackstrap Molasses eliminated my gray hair. I don't remember how long it took but I know hidden sources of MSG contribute to hair turning gray so you have to eliminate those sources also.
The body stores iron. I remember reading about the toxic levels so I'm going to look for that info in my latest nutrition book and get back to you. In the meantime I think one TBSP in 8-10 oz. of warm water or milk a day would be safe. (I use 2% milk and dilute that with water in winter because dairy cows are fed more corn or fodder to produce more milk then)
Please note our entire food supply has been engineered to last longer and has been tainted with GMO's. GMO grasses and grains are being fed to the animals we eat and get milk or eggs from. "Organic" is no longer safe because it is grown in soil that contains a genetically modified fungus. I posted this information elsewhere on EC but I just don't know where.
I'm going to copy excerpts from my 2007 Nutrition Almanac...
"The iron in the body is normally used efficiently. It is neither used up nor destroyed but is conserved to be used repeatedly; Excess iron, rather than being excreted, is stored; Too much iron, accumulating over the years, occurs often in older men. Iron overload can result in a condition called hemosiderosis, a term for excess iron storage in the body. Iron toxicity is the result of the inability of the digestive tract to eliminate excess iron. Symptoms of iron toxicity include fatigue, headaches, weight loss, nausea, vomiting, dizziness, shortness of breath, and a grayish color to the skin."