Iron Bisglycinate

Gentle, highly bioavailable chelated iron that minimizes digestive side effects while maximizing absorption

Scientific nameIron Bisglycinate Chelate FormulaC4H8FeN2O4 Molecular weight203.96 g/mol CAS20150-34-9

90 absorption score

7 safety / 10

30 USD per month

27 elemental iron %

6 documented interactions

Check it against something

Evidence level A

Iron Bisglycinate with:

99 out of 100

Works better together Compatible. Timing differs, so follow each supplement's own window.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Superior bioavailability

Better absorbed than sulfate and other common iron forms

Chelation protects iron from inhibitors and enhances uptake Evidence A-grade 2-4 weeks

Minimal digestive side effects

Significantly reduces nausea, constipation, and stomach upset

Chelated form bypasses common absorption issues Evidence A-grade Immediate

Effective anemia treatment

Rapidly corrects iron deficiency anemia

High bioavailability ensures efficient iron delivery Evidence A-grade 4-8 weeks

Enhanced energy and endurance

Improves energy levels and physical performance

Essential for oxygen transport and cellular energy production Evidence A-grade 4-12 weeks

Better cognitive function

Supports brain function and mental clarity

Brain requires high iron levels for neurotransmitter synthesis Evidence A-grade 6-12 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Probiotics for Autoimmune Disease Support Gut health & immune modulation 10-100 billion CFU daily B 60% Magnesium Glycinate Superior absorption sleep & muscle support 200-600 mg A 90% Magnesium Citrate Balanced absorption & digestive support 300-600 mg A 35% Chloride Electrolyte & digestive support 2300mg A 95% Bone Broth Collagen Gut healing & collagen support 20-40g powder B 85% Psyllium Husk Digestive health & cholesterol support 5-15g A 95%

Or a different form of the same thing

the comparison people search most

Iron Bisglycinate vs Iron Sulfate absorption 90 against 20 · $30 against $8 a month 20% Iron Bisglycinate vs Iron Fumarate absorption 90 against 25 · $30 against $18 a month 25% Iron Bisglycinate vs Heme Iron absorption 90 against 85 · $30 against $120 a month 85%

All Iron forms ranked by absorption →

Every pair we checked

12 combinations scored by the engine

Iron Bisglycinate + Calcium Carbonate Inhibits iron absorption Needs attention 40

Iron Bisglycinate + Zinc Gluconate Competes with iron for absorption Needs attention 40

Iron Bisglycinate + Turmeric May reduce iron absorption Needs attention 61

Iron Bisglycinate + Caffeine No documented interaction either way No known interaction 70

Iron Bisglycinate + Creatine Monohydrate No documented interaction either way No known interaction 70

Iron Bisglycinate + Whey Protein No documented interaction either way No known interaction 70

Iron Bisglycinate + Lactase No documented interaction either way No known interaction 70

Iron Bisglycinate + Bovine Collagen No documented interaction either way No known interaction 70

Iron Bisglycinate + DHA No documented interaction either way No known interaction 70

Iron Bisglycinate + Copper Bisglycinate High iron may compete with copper absorption Needs attention 82

Iron Bisglycinate + Vitamin D3 Dramatically enhances iron absorption Works better together 94 Iron Bisglycinate + Vitamin C (Ascorbic Acid) Dramatically enhances iron absorption Works better together 99

Dosage

With vitamin c between meals

Daily18-65 mg elemental

Maintenance8-18 mg elemental

Deficiency treatment25-65 mg elemental

Pregnancy27-30 mg elemental

Elemental ironContains ~20% elemental iron

Upper limit 45 mg NIH ODS

Before you take it

Pregnancycommonly recommended

VeganYes

When to expect it

First Effects2-4 weeks for energy improvements

Peak Benefits8-16 weeks for complete anemia correction

Deficiency DevelopmentWeeks to months depending on stores

Toxicity OnsetMonths with excessive intake

How to measure it

$80-150

MarkerSerum ferritin, hemoglobin, iron, TIBC

OptimalFerritin: 30-150 ng/mL, Hemoglobin: 12-16 g/dL

Deficient belowFerritin: <15 ng/mL, Hemoglobin: <12 g/dL

FrequencyEvery 3-6 months when treating deficiency

What people actually reported to the FDA

CAERS, 340 reports naming it as the suspect

Most reported effects

Vomiting 33

Dyspnoea 31

Diarrhoea 28

Nausea 24

Hypersensitivity 23

Named as the suspect 340 reports of 1,000+ that mention it at all

Serious outcome 84% hospitalisation, emergency room or worse

Other Serious or Important Medical Event228

Hospitalization85

Visited Emergency Room65

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Elemental iron 27.4% of 203.96 g/mol

Absorption Very high 90 of 100 · best absorbed form of this compound

Delivered daily 10.2 mg

Cost per 100 mg delivered $9.77 comparative — uses the absorption score, not a measured percentage

A 500 mg capsule of Iron Bisglycinate contains 137 mg of iron. How much of that crosses into your blood is not measured for this form — the absorption score ranks it against other forms, it is not a share of the dose. How this is calculated →

Works better with

3 documented

Vitamin C

Dramatically enhances iron absorption

Reduces iron to more absorbable ferrous form · level A

Vitamin A

Improves iron utilization and storage

Required for iron mobilization from storage · level A

Copper

Essential for iron utilization

Required for iron transport and hemoglobin synthesis · level A

What not to take with Iron Bisglycinate

3 documented

Calcium

Inhibits iron absorption

Competition for intestinal transporters · major significance

Zinc High Dose

Competes with iron for absorption

Shared intestinal transport mechanisms · moderate significance

Tannins Phytates

Reduce iron absorption

Bind iron making it unavailable for absorption · moderate significance

Medication interactions

Discuss these with a pharmacist before combining

tetracycline-antibiotics Major

Iron reduces antibiotic absorption

What to do: Space doses 2-4 hours apart

levothyroxine Major

Iron reduces thyroid hormone absorption

What to do: Take iron 4+ hours away from thyroid medication

proton-pump-inhibitors Moderate

Acid blockers reduce iron absorption

What to do: Chelated iron may overcome this interaction

Available forms

bioavailability compared

Best absorbed form of Iron — 90% against 3 alternatives. Compare all forms →

Iron Bisglycinate Chelate 90

Iron Bisglycinate Chelate: Superior absorption, Gentle on stomach, Non-constipating, High tolerance

Food sources

before you supplement

Iron bisglycinate not found naturally in foods Only available as supplement · 90

Red meat (heme iron) 2-3mg per 100g · 25

Spinach (non-heme iron) 2.7mg per 100g cooked · 5

Fortified cereals 4-18mg per serving · 10

Too little

deficiency signs

Fatigue and weakness
Pale skin, nails, and inner eyelids
Shortness of breath and heart palpitations
Cold hands and feet
Brittle or spoon-shaped nails
Restless leg syndrome
Cravings for ice or starch

Too much

toxicity signs

Acute: nausea, vomiting, diarrhea
Chronic: liver damage and cirrhosis
Heart problems and diabetes
Joint pain and arthritis
Skin pigmentation changes
Fatigue and weakness (ironically)

Who benefits most

iron-deficiency-anemia

Most effective and tolerable form for treating deficiency

25-65 mg daily (elemental iron)

pregnant-women

Gentle form with superior tolerance during pregnancy

27-30 mg daily (as recommended by healthcare provider)

digestive-sensitive-individuals

Minimal side effects compared to other iron forms

18-25 mg daily

athletes-endurance

Superior bioavailability for performance and recovery

18-30 mg daily

vegetarian-vegan

Enhanced absorption for those avoiding heme iron sources

18-32 mg daily

Where to buy it

compare forms first

Look for Iron Bisglycinate at 18-65 mg elemental per serving. The form that matters here is Iron Bisglycinate Chelate.

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What else affects it

Beyond other supplements

Tannins phytates

Reduce iron absorption

Bind iron making it unavailable for absorption

How it works

Chelated form protects iron from dietary inhibitors
Essential component of hemoglobin and myoglobin
Critical for cellular respiration and energy production
Required for DNA synthesis and cell division
Essential for neurotransmitter synthesis
Involved in immune function and collagen synthesis

Key findings

what the evidence supports

Superior bioavailability vs iron sulfate (absorption studies)
Significantly better tolerance with fewer side effects (clinical trials)
Effective for treating iron deficiency anemia (medical literature)
Preferred form for pregnancy supplementation (obstetric studies)

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Iron Bisglycinate?

Documented effects: Superior bioavailability; Minimal digestive side effects; Effective anemia treatment; Enhanced energy and endurance. Better absorbed than sulfate and other common iron forms

How much Iron Bisglycinate should you take per day?

The common daily range is 18-65 mg elemental. By goal — maintenance: 8-18 mg elemental; deficiency treatment: 25-65 mg elemental; pregnancy: 27-30 mg elemental; elemental iron: Contains ~20% elemental iron.

When is the best time to take Iron Bisglycinate?

With vitamin c between meals. First effects are typically reported within 2-4 weeks for energy improvements.

What are the side effects of Iron Bisglycinate?

At excessive doses: Acute: nausea, vomiting, diarrhea, Chronic: liver damage and cirrhosis, Heart problems and diabetes, Joint pain and arthritis, Skin pigmentation changes. Safety rating at normal doses is 7 out of 10.

What should you not take with Iron Bisglycinate?

Separate it from Calcium, Zinc High Dose, Tannins Phytates by two to four hours. Inhibits iron absorption

Does Iron Bisglycinate interact with medications?

Documented interactions with tetracycline-antibiotics, levothyroxine, proton-pump-inhibitors. Discuss these with a pharmacist before combining.

How much Iron Bisglycinate is too much?

The tolerable upper intake level is 45 mg per day for adults, per NIH ODS. Above that, the risk of adverse effects rises: Acute: nausea, vomiting, diarrhea, Chronic: liver damage and cirrhosis, Heart problems and diabetes.

How do you know if you need Iron Bisglycinate?

The marker is Serum ferritin, hemoglobin, iron, TIBC, optimal range Ferritin: 30-150 ng/mL, Hemoglobin: 12-16 g/dL. Common deficiency signs: Fatigue and weakness, Pale skin, nails, and inner eyelids, Shortness of breath and heart palpitations, Cold hands and feet.

Taken for

74 Digestion

Lactase · Lactobacillus acidophilus · Protease