Iron Bisglycinate

Iron bisglycinate is a chelated form of iron, meaning the metal is enclosed within an organic molecule rather than existing as a simple salt ^[1]. Specifically, one atom of ferrous iron is bound to two molecules of glycine, the smallest amino acid, producing a stable, low-molecular-weight compound sometimes sold under the trade name Ferrochel ^[1]. It belongs to a broader category of amino acid iron chelates developed as alternatives to traditional iron salts for supplements and food fortification ^[1].

The appeal of the chelate rests on the difficulties of ordinary iron supplements ^[2]. Iron salts such as ferrous sulfate are effective but poorly tolerated by many people, frequently causing nausea, constipation, an unpleasant metallic taste, and stomach discomfort, which leads some to stop taking them ^[2]. In addition, non-heme iron from salts is easily bound by components of food and drink that reduce its absorption ^[1]. By locking the iron inside glycine, ferrous bisglycinate is intended to resist these interactions, improve absorption, and reduce the amount of free iron irritating the digestive tract ^[1].

Clinical studies have compared iron bisglycinate with ferrous sulfate for correcting iron deficiency ^[2]. In one trial in pregnant women, supplementation with the bisglycinate chelate improved hemoglobin and iron stores more effectively than ferrous sulfate even though a lower amount of iron was given, and it was associated with better tolerance and fewer complaints about taste ^[2]. Other trials, such as one in anemic schoolchildren, found the chelate and ferrous sulfate to be similarly effective at raising hemoglobin ^[3]. More recent comparative work in animals has continued to examine the absorption and gastrointestinal tolerability of ferrous bisglycinate alongside other iron forms ^[4]. Overall, the evidence supports it as an effective iron source, with a possible advantage in tolerability, though findings are not uniform across studies ^[3][4].

Iron bisglycinate is widely used as an over-the-counter dietary supplement and as a fortificant added to foods, and it is generally recognized as safe for these purposes in many countries ^[1]. It is taken to prevent or treat iron deficiency and iron-deficiency anemia, and is often chosen by people who cannot tolerate conventional iron tablets ^[2]. Like all iron products it can still cause digestive side effects in some users, its darker stools are expected, and, importantly, it carries the same risk of iron overload and of dangerous overdose, especially in children, so it should be used only when iron is actually needed ^[2].

Generally better tolerated than ferrous sulfate, with less constipation and nausea, though gut side effects still happen. Overload risk is the same as any iron form, so don't stack it on top of an already-replete state. Keep away from children.