Iron Bisglycinate provides an optimal way to supplement iron, which is essential for red blood cell formation.* Supplementing with iron helps fight fatigue and other symptoms of iron deficiency in athletes and others.* The U.S. Centers for Disease Control has determined that the prevalence of iron deficiency is greatest among toddlers (7% of those ages 1-2 years) and menstruating adolescent and adult females (9-16 % of individuals ages 12-49, whether they are athletes or not. Conventional iron supplementation, including forms such as ferrous sulfate, can cause gastrointestinal side effects – including nausea, vomiting, constipation, diarrhea, and dark-colored stools – because these conventional forms of iron are poorly absorbed. Thorne's Iron Bisglycinate provides 25 mg of elemental iron per capsule that has been reacted with glycine for optimal absorption in the gastrointestinal tract, thus helping to decrease the typical gastrointestinal side effects.* Thorne's Iron Bisgylcinate is NSF Certified for Sport®.