How many milligrams of elemental iron are present in a 25 mg dose of iron bisglycinate?

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Last updated: October 9, 2026 • View editorial policy

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Elemental Iron Content in Iron Bisglycinate

A 25 mg dose of iron bisglycinate contains 25 mg of elemental iron 1.

Key Information from Guidelines

According to the 2024 AGA Clinical Practice Update on Management of Iron Deficiency Anemia, ferrous bisglycinate formulations list "25 mg per tablet" as the approximate elemental iron content 1. This is notably different from other iron formulations where the tablet size refers to the total compound weight rather than elemental iron content.

Comparison with Other Iron Formulations

For context, other common oral iron preparations show a clear distinction between compound weight and elemental iron:

  • Ferrous sulfate: 200 mg tablet contains only 65 mg elemental iron
  • Ferrous gluconate: 325 mg tablet contains only 27-38 mg elemental iron
  • Ferrous fumarate: 210 mg tablet contains 69 mg elemental iron

Iron bisglycinate is unique in that the labeled dose directly represents the elemental iron content 1.

Clinical Evidence Supporting This Dosing

Multiple high-quality randomized trials confirm this dosing convention:

  • A 2014 randomized trial specifically compared "ferrous bisglycinate 25 mg elemental iron" versus "ferrous sulfate 50 mg elemental iron" 2
  • A 2024 study evaluated "25 mg of elemental iron as ferrous bisglycinate" 3
  • A 2022 trial used "ferrous bisglycinate (equiv. iron 24 mg)" 4

Important Clinical Consideration

This lower elemental iron dose (25 mg) in bisglycinate formulations is therapeutically effective and actually offers advantages over higher-dose conventional iron salts 2. The bisglycinate chelate structure enhances absorption and reduces gastrointestinal side effects, allowing for effective iron repletion at approximately half the elemental iron dose of ferrous sulfate 3, 4, 2.

References

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.