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
energy and exercise tolerance climb as ferritin rebuilds
Retest at 8–12 weeks
confirm stores, do not over-supplement
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.
Usage
Entry Dose
18mg elemental
Standard Dose
25–36mg elemental
Max Dose
45mg elemental
Onset
4–8 weeks (ferritin)
Combinations
Pairs well with
Synergistic
Vitamin C — dramatically increases non-heme iron absorption
Vitamin B12 + folate — iron deficiency anemia often coexists; address all three together
Lactoferrin — enhances iron utilization and reduces oxidative stress from free iron
Avoid combining
Contraindicated
Calcium — strongly inhibits iron absorption; separate by at least 2 hours
Zinc / magnesium — compete for divalent metal transporter; separate doses
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.
Strong (human RCTs / meta-analyses)
Strong evidence applies specifically to correcting diagnosed iron-deficiency anemia; supplementing without a confirmed deficiency is not advised and can be harmful.
Milman N (2011). Annals of Hematology. Review (iron deficiency anemia treatment). PMID: 21625892.