Iron Bisglycinate
Research Reliability -
A gentle, well-absorbed iron chelate that replenishes iron stores and supports energy, focus, and red blood cell production.
Appetite
Mood
Sleep
Iron Bisglycinate
Description
Iron bisglycinate provides elemental iron bonded to glycine in a form that is significantly better absorbed and far gentler on the digestive tract than ferrous sulfate or ferric forms. Iron is essential for hemoglobin synthesis and oxygen transport, and deficiency is one of the most common nutritional deficiencies worldwide, particularly in menstruating women and athletes. Symptoms of low iron include fatigue, brain fog, poor exercise tolerance, and difficulty concentrating. This chelated form is ideal for those who have struggled with digestive side effects from other iron supplements.
Effects
First 2 weeks
subtle
Weeks 4–8
Retest at 8–12 weeks
How It Feels
If you were iron-deficient, the return of energy over a month can feel dramatic; the fog lifts and stairs stop feeling hard. The gentle glycinate form avoids the constipation of standard iron. Never take iron long term without a blood test, since excess is harmful.
Evidence
Evidence Strength
Strong (human RCTs / meta-analyses)
Caveats
Strong evidence applies specifically to correcting diagnosed iron-deficiency anemia; supplementing without a confirmed deficiency is not advised and can be harmful.
Usage
Commonly Referenced Starting Amount
15 mg elemental iron/day
Commonly Referenced Amount
18–60 mg elemental iron/day, with the higher end used for treating diagnosed deficiency
Referenced Upper Limit
45 mg/day is the IOM upper limit for general use, set by GI distress and overload risk; therapeutic anemia doses above this are used under medical supervision
Onset
4–8 weeks (ferritin)
Biomarkers to Track
Subjective
(Daily)
Energy and fatigue levels (1–10)
Exercise endurance and recovery
Coldness in hands and feet
Objective
(Quarterly)
Serum ferritin level
Hemoglobin and hematocrit
TIBC (iron binding capacity)
Effective but genuinely risky to over-supplement. Excess iron is toxic and iron is a leading cause of poisoning in children.
Anyone not confirmed low by a blood test, men and postmenopausal women especially, and those with hemochromatosis.
Taking iron without testing ferritin first, and pairing it with coffee or calcium, which block absorption.
Disclaimer
This information is for educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a health condition.
Milman N (2011). Annals of Hematology. Review (iron deficiency anemia treatment). PMID: 21625892.
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