Home Ingredients Ferrous Bisglycinate
Bone HealthImmune Support

Ferrous Bisglycinate

Evidence Level
Strong
2 Clinical Trials
5 Documented Benefits
4/5 Evidence Score

Ferrous bisglycinate is iron chelated with two glycine molecules — a newer form distinguished by superior tolerability vs ferrous sulfate while maintaining good absorption. Meta-analyses show iron bisglycinate is more effective than other iron salts for raising hemoglobin in pregnant women, with significantly fewer GI side effects. Particularly valuable for pregnancy, IBD, or any patient who cannot tolerate sulfate.

Studied Dose 25-60 mg elemental iron/day; pregnancy: 25-30 mg/day often sufficient
Active Compound Ferrous bisglycinate (Fe-bisglycinate chelate)

Benefits

Superior GI Tolerability

Iron bisglycinate causes substantially fewer GI side effects than ferrous sulfate — less constipation, nausea, and gastric pain. Rate of patients quitting therapy is much lower. Critical advantage for chronic supplementation, pregnancy, and IBD populations.

Supported by Trial 2, Trial 1

Better Absorption Than Sulfate

Some research suggests ferrous bisglycinate is up to 4× more bioavailable than ferrous sulfate; meta-analysis showed iron bisglycinate more effective than other salts for raising hemoglobin in pregnant women.

Supported by Trial 1

Resistance to Absorption Inhibitors

The chelate structure protects iron from common absorption inhibitors — phytates (in cereals/grains), oxalates (in spinach), polyphenols (in coffee/tea). Means more reliable absorption when taken with meals.

Supported by Trial 1

Pregnancy Iron Supplementation

Pregnancy iron requirements increase substantially (RDA 27 mg/day vs 18 mg pre-pregnancy). Ferrous bisglycinate's tolerability is particularly valuable when nausea/morning sickness already strain GI comfort.

Supported by Trial 2, Trial 1

IBD/Crohn's/Ulcerative Colitis

Inflammatory bowel disease patients often have iron deficiency but cannot tolerate ferrous sulfate (worsens GI symptoms, may aggravate inflammation). Bisglycinate is gentler alternative for these populations.

Supported by Trial 2, Trial 1

Mechanism of action

1

Glycine Chelate Stability

Iron ion bonded to two glycine molecules in stable chelate. Resists gastric pH changes and competing absorption inhibitors. Absorbed via standard iron transport (DMT1) AND potentially via dipeptide transporters as an intact glycine complex.

2

Reduced Free Iron in GI Tract

Free Fe²⁺ in GI tract generates reactive oxygen species that damage mucosal cells — basis for ferrous sulfate's GI symptoms. Chelated bisglycinate keeps iron bound through transit, reducing free-iron-mediated mucosal damage.

3

Bypass of Absorption Inhibitors

Phytates and polyphenols bind free iron and reduce absorption — but cannot displace iron from the bisglycinate chelate. Iron arrives at duodenal absorption sites still bound and intact.

4

Standard Iron Functions

Once absorbed, iron functions identically regardless of supplemental form — incorporated into hemoglobin (oxygen transport), myoglobin (muscle oxygen storage), cytochromes (electron transport), iron-sulfur cluster enzymes.

Clinical trials

1
Iron Bisglycinate for Pregnancy IDA — Pineda 2018 Meta-Analysis
PubMed

Meta-analysis comparing iron bisglycinate vs other iron salts for IDA treatment in pregnant women.

Pooled across pregnancy IDA RCTs.

Iron bisglycinate was significantly MORE effective than other iron salts (sulfate, fumarate) at raising hemoglobin in pregnant women, with SIGNIFICANTLY FEWER GI side effects. Important comparative evidence supporting bisglycinate as preferred form for pregnancy IDA.

2
Ferrous Bisglycinate Tolerability vs Sulfate — RCTs
PubMed

Multiple RCTs comparing ferrous bisglycinate vs ferrous sulfate for tolerability and adherence in IDA patients.

Pooled across tolerability trials.

Ferrous bisglycinate causes substantially fewer GI side effects (constipation, nausea, abdominal pain) vs ferrous sulfate. Adherence rates higher. Supports bisglycinate as preferred form for tolerability-sensitive populations.

Side effects and drug interactions

Common Potential side effects

Generally much better-tolerated than ferrous sulfate.
Mild GI distress at high doses.
Constipation — less common but still possible.
Dark stools — expected, harmless.
Metallic taste rare with chelate form.
PEDIATRIC IRON POISONING — same caution as all iron forms; child-resistant packaging mandatory.

Important Drug interactions

Same general iron interactions: tetracyclines, quinolones, levothyroxine, bisphosphonates, levodopa — separate by 2-4 hours.
Calcium — competes for absorption; separate dosing.
PPIs/antacids — reduce iron absorption.
Vitamin C — enhances absorption.
Coffee/tea tannins — chelation protection means LESS interference than with sulfate, but still recommend separation.
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Frequently asked questions about Ferrous Bisglycinate

What is Ferrous Bisglycinate?

Ferrous bisglycinate is iron chelated with two glycine molecules — a newer form distinguished by superior tolerability vs ferrous sulfate while maintaining good absorption.

What does Ferrous Bisglycinate do?

Iron ion bonded to two glycine molecules in stable chelate. Resists gastric pH changes and competing absorption inhibitors. Absorbed via standard iron transport (DMT1) AND potentially via dipeptide transporters as an intact glycine complex. In clinical research, Ferrous Bisglycinate has been studied for superior gi tolerability, better absorption than sulfate, resistance to absorption inhibitors.

Who should take Ferrous Bisglycinate?

Ferrous Bisglycinate may be most relevant for people interested in bone health, immune support. It has been clinically studied for superior gi tolerability, better absorption than sulfate, resistance to absorption inhibitors. As with any supplement, consult your healthcare provider before starting, especially if you have medical conditions or take prescription medications.

How long does Ferrous Bisglycinate take to work?

Most clinical trial effects appear over weeks of consistent use; individual response varies. Acute or same-day effects (where applicable) typically appear within hours, but most cumulative benefits — particularly those affecting biomarkers, mood, sleep quality, or chronic symptoms — require 4-12 weeks of regular use to fully assess. If you don't notice benefit after 12 weeks at the appropriate dose, it may not be your responder.

When is the best time to take Ferrous Bisglycinate?

Ferrous Bisglycinate can typically be taken with breakfast or dinner — taking with food reduces GI sensitivity for most supplements. Specific timing matters less than daily consistency for cumulative effects. Always check product labeling and follow personalized guidance from your healthcare provider.

Is Ferrous Bisglycinate worth taking?

Ferrous Bisglycinate has strong clinical evidence (Evidence Level 4/5 on NutraSmarts) for its primary uses, with multiple randomized controlled trials and meta-analyses supporting its benefits. Whether it's worth taking depends on your specific goals, what you've already tried, your budget, and your overall supplement strategy. The honest framing: no supplement is essential for most people, and lifestyle factors (sleep, exercise, diet, stress management) typically produce larger effects than any single supplement. Ferrous Bisglycinate is most worth trying if its evidence-supported uses align with your specific goals.

What is the recommended dosage of Ferrous Bisglycinate?

The clinically studied dose for Ferrous Bisglycinate is 25-60 mg elemental iron/day; pregnancy: 25-30 mg/day often sufficient. Always follow product labeling and consult a healthcare provider for personalized dosing recommendations.

What is Ferrous Bisglycinate used for?

Ferrous Bisglycinate is studied for superior gi tolerability, better absorption than sulfate, resistance to absorption inhibitors. Iron bisglycinate causes substantially fewer GI side effects than ferrous sulfate — less constipation, nausea, and gastric pain. Rate of patients quitting therapy is much lower.