Outside of training deficiencies, low iron is one of the most common reasons for poor results during workouts and races. Recent research indicates that almost 56% of male runners and 86% of female runners suffer from an iron deficiency that severely hampers performance. Thus, there is a very good chance you have low iron levels and could see improvement from supplementing from iron. Mas Iron has been proven to be better than any current iron supplement on the market, so if you need to raise your iron levels it’s your best choice.