Iron in a form for improved absorption without gastrointestinal side effects. Ferrous bisglycinate is the optimal way to replenish iron, which is necessary for the formation of red blood cells. It helps fight fatigue and other symptoms of iron deficiency in athletes and other people. NSF Certified for Sport. Thorne Iron Bisglycinate is NSF Certified for Sport. It is necessary for the formation of red blood cells. The US Centers for Disease Control has found that the prevalence of iron deficiency is highest among toddlers (7% of children aged 1 to 2 years), menstruating adolescents, and adult women (9–16% of people aged 12–49 years) , regardless of whether they are athletes or not. Common iron supplements, including forms such as ferrous sulfate, may cause gastrointestinal side effects including nausea, vomiting, constipation, diarrhea, and dark-colored stools, as these are common in pregnant and nursing women.
