mineralOTC supplementIron overdose is a leading cause of poisoning deaths in young childrenSupplementing without a documented deficiency risks iron overload
Iron (ferrous bisglycinate)Benefits, Dosage & Interactions
Also known as: ferrous
Iron is an essential mineral vital for numerous bodily functions. Ferrous bisglycinate is a form of iron that is chelated to two glycine molecules. Research on Iron (ferrous bisglycinate) focuses on fertility, healthy aging, and women's healthspan. It is typically taken in the morning.
How much Iron (ferrous bisglycinate) do people take?
Ferrous bisglycinate trials pooled in the review used roughly 15-60 mg/day of elemental iron. Route reported: Oral tablets or capsules. Frequency reported: Once daily, or alternate-day dosing in some trials to limit hepcidin-driven blockade. These are amounts documented in the cited studies and labels for Iron (ferrous bisglycinate) — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Moderate — Covered by a systematic review, without regulatory approval.
Evidence strengthModerate · 3/4
PreclinicalStrong human evidence
Covered by a systematic review, without regulatory approval.
Why does elemental iron matter on a supplement label?
The weight of an iron salt is not the same as its elemental iron content. Compare the labeled elemental amount and formulation; do not compare products only by the larger chemical-compound weight.
Source: NIH ODS iron fact sheet
Browse compound evidence cardsWhole-body biological half-life
Not applicable
Typical timing
in the morning
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Iron (ferrous bisglycinate) in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Iron (ferrous bisglycinate) entry is written from. Each number matches an inline marker above.
- [1]The effects of oral ferrous bisglycinate supplementation on hemoglobin and ferritin concentrations in adults and children: a systematic review and meta-analysisFischer JAJ, Cherian AM, Bone JN, et al. · Nutrition Reviews · 2023 · Peer-reviewed · PMID 36728680
- [2]Daily oral iron supplementation during pregnancyFinkelstein JL, Cuthbert A, Weeks J, et al. · Cochrane Database of Systematic Reviews · 2024 · Peer-reviewed · PMID 39145520
References & Evidence
Sources on this page that document Iron (ferrous bisglycinate) dosing, timing and safety.
- [2]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Iron (ferrous bisglycinate) studied for?
What is Iron (ferrous bisglycinate)?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Iron is an essential mineral vital for numerous bodily functions. Ferrous bisglycinate is a form of iron that is chelated to two glycine molecules. This chelation makes it more readily absorbed by the body compared to some other iron compounds and generally causes fewer gastrointestinal side effects. It is primarily used to prevent or treat iron deficiency and iron deficiency anemia.
Iron deficiency is a common nutritional deficiency globally, affecting a significant portion of the population, particularly women, children, and individuals with certain medical conditions. Symptoms can include fatigue, weakness, pale skin, shortness of breath, dizziness, and restless legs syndrome. (NIH ODS - Iron)
What does the research say about Iron (ferrous bisglycinate)?
Tap a section to expand.
Iron's primary mechanism of action involves its role in hemoglobin production. Hemoglobin is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. Without sufficient iron, the body cannot produce enough hemoglobin, leading to iron deficiency anemia.
Beyond oxygen transport, iron is also a crucial component of myoglobin, a protein that carries and stores oxygen in muscle tissues. It is involved in various enzymatic reactions, including those essential for energy metabolism, DNA synthesis, and immune function. (NIH ODS - Iron)
Ferrous bisglycinate, specifically, is a chelated form of iron. The iron ion (Fe2+) is bound to two molecules of the amino acid glycine. This chelation protects the iron from interactions with certain dietary components (like phytates or tannins) that can inhibit absorption. It also allows the iron to be absorbed intact through a different pathway than inorganic iron salts, potentially leading to higher bioavailability and reduced gastrointestinal upset. Studies suggest it is absorbed better than ferrous sulfate in some populations. (Cochrane Review on Iron Supplementation, PubChem - Ferrous Bisglycinate)
Source for this section: Sources for How does Iron (ferrous bisglycinate) work?: Jumps to this entry in the sources and references list at the end of the page.
The primary benefit of iron supplementation, especially with well-absorbed forms like ferrous bisglycinate, is the prevention and treatment of iron deficiency and iron deficiency anemia.
* **Treating Iron Deficiency Anemia:** By providing the body with sufficient iron, ferrous bisglycinate helps restore hemoglobin levels, improving oxygen transport and alleviating symptoms of anemia such as fatigue, weakness, and shortness of breath. (NIH ODS - Iron)
* **Preventing Iron Deficiency:** It is often used in populations at high risk of iron deficiency, including pregnant women, menstruating women, infants, children, and individuals with malabsorption conditions or chronic blood loss. (NIH ODS - Iron)
* **Supporting Cognitive Function:** Iron plays a role in neurotransmitter synthesis and myelination. Correcting iron deficiency, especially in children, can improve cognitive function and development. (Cochrane Review on Iron Supplementation)
* **Boosting Immune Function:** Iron is essential for the proper functioning of immune cells. Adequate iron levels support a healthy immune response. (NIH ODS - Iron)
* **Reducing Restless Legs Syndrome Symptoms:** Iron supplementation has been shown to alleviate symptoms of restless legs syndrome in individuals with low iron stores. (Mayo Clinic - Restless Legs Syndrome)
Source for this section: Sources for What is Iron (ferrous bisglycinate) used for?: Jumps to this entry in the sources and references list at the end of the page.
Numerous studies support the efficacy of iron supplementation for treating iron deficiency and iron deficiency anemia. The NIH ODS (Office of Dietary Supplements) provides comprehensive information on iron, including its roles, deficiency, and dietary sources, emphasizing its critical importance.
A Cochrane Review on iron supplementation for anemia in pregnancy concluded that iron supplementation effectively prevents and treats iron deficiency anemia in pregnant women. While this review often includes various forms of iron, ferrous bisglycinate specifically has been highlighted in other research for its superior absorption and tolerability compared to traditional iron salts.
PubChem, a database of chemical compounds, describes ferrous bisglycinate's chemical properties and its use as a dietary iron source, noting its high bioavailability. Research comparing ferrous bisglycinate to ferrous sulfate often indicates that ferrous bisglycinate can achieve similar increases in hemoglobin with lower doses or fewer side effects, making it a preferred option for some individuals. (MedlinePlus - Iron)
Source for this section: Sources for How strong is the evidence for Iron (ferrous bisglycinate)?: Jumps to this entry in the sources and references list at the end of the page.
While generally well-tolerated, especially compared to other iron forms, ferrous bisglycinate can still cause some side effects, primarily dose-dependent.
Common side effects include:
* Constipation
* Diarrhea
* Nausea
* Stomach upset or cramps
* Darkening of stools (this is common and harmless due to unabsorbed iron)
Less common or severe side effects (often associated with very high doses or iron overdose)include:
* Vomiting
* Abdominal pain
* Metallic taste
* Heartburn
To minimize gastrointestinal side effects, iron supplements are sometimes recommended to be taken with food, although this can sometimes slightly reduce absorption. Starting with a lower dose and gradually increasing it may also help. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Individuals with certain medical conditions should exercise caution or avoid iron supplementation:
* **Hemochromatosis:** This genetic disorder causes excessive iron absorption and accumulation, which can lead to organ damage. Iron supplementation is contraindicated in these individuals. (NIH ODS - Iron)
* **Hemosiderosis:** Similar to hemochromatosis, this involves iron overload. (NIH ODS - Iron)
* **Porphyria Cutanea Tarda:** Iron overload can exacerbate this skin condition. (Mayo Clinic)
* **Sickle Cell Anemia or Thalassemia:** While iron deficiency can occur, these conditions can also involve iron overload from frequent blood transfusions. Iron supplementation should only be taken under strict medical supervision. (MedlinePlus)
* **Inflammatory Bowel Disease (IBD):** Iron can sometimes worsen inflammation in conditions like Crohn's disease or ulcerative colitis. (Mayo Clinic)
Parents should be extremely careful with iron supplements, as accidental overdose is a leading cause of poisoning deaths in young children. Keep all iron supplements out of reach of children. (NIH ODS - Iron)
Do not exceed the recommended dose; high iron intake can be toxic and lead to serious health problems. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Iron (ferrous bisglycinate) is contraindicated in individuals with:
* **Known hypersensitivity** to iron compounds.
* **Hemochromatosis or other iron overload syndromes** (e.g., hemosiderosis, hereditary hemochromatosis). Taking additional iron will worsen these conditions and can lead to severe organ damage. (NIH ODS - Iron)
* **Non-iron deficiency anemias** (e.g., megaloblastic anemia, aplastic anemia, hemolytic anemia) unless iron deficiency is also present, as iron supplementation will not resolve the underlying anemia and could lead to iron overload. (MedlinePlus - Iron)
* **Repeated blood transfusions:** Patients receiving frequent transfusions are at risk for iron overload and should not take iron supplements without explicit medical guidance. (DrugBank - Ferrous Bisglycinate)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Iron can interact with several medications and dietary components, affecting either iron absorption or the absorption/efficacy of other substances:
* **Calcium Supplements and Dairy Products:** Calcium can inhibit iron absorption. It is generally recommended to take iron and calcium supplements at different times of the day (at least 2 hours apart). (NIH ODS - Iron)
* **Antacids (containing calcium or magnesium):** These can interfere with iron absorption. Take iron at least 2 hours apart from antacids. (MedlinePlus - Iron)
* **Proton Pump Inhibitors (PPIs) and H2 Blockers:** Medications that reduce stomach acid (e.g., omeprazole, ranitidine) can decrease iron absorption, as gastric acid helps convert dietary iron into an absorbable form. (DrugBank - Ferrous Bisglycinate)
* **Certain Antibiotics:**
* **Tetracyclines:** Iron can bind to tetracycline antibiotics (e.g., doxycycline) and reduce the absorption of both. Take iron at least 2-4 hours apart from tetracyclines.
* **Quinolone Antibiotics:** (e.g., ciprofloxacin, levofloxacin) Iron can also reduce the absorption of quinolone antibiotics. Take iron at least 2-4 hours apart. (MedlinePlus - Iron)
* **Levothyroxine (Thyroid Hormone):** Iron can interfere with the absorption of levothyroxine, making it less effective. Take these medications several hours apart. (FDA Label - Levothyroxine)
* **Bisphosphonates (for osteoporosis):** Iron can reduce the absorption of bisphosphonates (e.g., alendronate). Administer several hours apart. (EMA SmPC - Alendronic Acid)
* **Tea, Coffee, and Phytate-rich Foods (e.g., whole grains, legumes):** These can hinder iron absorption due to compounds like tannins and phytates. It's often recommended to take iron supplements away from these foods/beverages or with vitamin C-rich foods to enhance absorption. Ferrous bisglycinate may be less affected by some of these inhibitors than inorganic iron salts, but separation is still prudent. (NIH ODS - Iron)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
The typical timing for taking iron (ferrous bisglycinate) is in the morning, often on an empty stomach to maximize absorption. However, if gastrointestinal upset occurs, it can be taken with food. To enhance absorption, it is frequently recommended to take iron with vitamin C (e.g., with orange juice or a vitamin C supplement). Avoid taking it simultaneously with calcium, dairy products, antacids, or certain medications, as these can interfere with absorption. A separation of at least 2 hours is generally advised for such interactions.
Source for this section: Sources for When should you take Iron (ferrous bisglycinate)?: Jumps to this entry in the sources and references list at the end of the page.
Put it into practice
Reading about Iron (ferrous bisglycinate) is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.
What interacts with Iron (ferrous bisglycinate)?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Calcium | Caution | Compound pairConfidence: theoretical | Calcium competes with iron for absorption, so taking large doses together reduces iron uptake.Source pending | Separate them by at least 2 hours.Suggested separation: 2 h |
| Vitamin C | Complementary | Compound pairConfidence: theoretical | Vitamin C increases absorption of non-heme (supplement) iron.Source pending | Fine to take together; no need to separate. |
| Levothyroxine | Caution | Compound pairConfidence: theoretical | Iron reduces absorption of thyroid medication when taken together.Source pending | Separate by about 4 hours.Suggested separation: 4 h |
| Any + | Caution | Category ruleConfidence: theoretical | Divalent cations chelate levothyroxine in the gut and reduce absorption by up to 30%.Source pending | Take levothyroxine on empty stomach; separate mineral supplements by at least 4 hours.Suggested separation: 4 h |
| Liothyronine | Caution | Compound pairConfidence: theoretical | Minerals chelate T3 and reduce absorption.Source pending | Separate liothyronine and mineral supplements by at least 4 hours.Suggested separation: 4 h |
| Caffeine | Caution | Compound pairConfidence: theoretical | Polyphenols in coffee/tea inhibit non-heme iron absorption by up to 60%.Source pending | Take iron away from coffee and tea by at least 2 hours.Suggested separation: 2 h |
Frequently asked questions about Iron (ferrous bisglycinate)
Ferrous bisglycinate is a chelated form of iron, meaning the iron is bound to amino acids (glycine). This chemical structure generally makes it more bioavailable and causes fewer gastrointestinal side effects (like constipation and stomach upset) compared to non-chelated forms like ferrous sulfate. Ferrous sulfate is typically less expensive but may require higher doses or be less tolerated.
Yes, you can take iron with food if you experience stomach upset when taking it on an empty stomach. While some food components, particularly calcium and phytates (in whole grains and legumes), can reduce absorption, ferrous bisglycinate is generally less affected than other iron forms. Taking it with vitamin C-rich foods can actually enhance absorption.
Iron (ferrous bisglycinate) can take several weeks to a few months for iron supplements to significantly raise hemoglobin levels and alleviate symptoms of iron deficiency anemia. Your clinician will typically monitor your blood iron levels and hemoglobin to determine the effectiveness and duration of treatment. Building up iron stores (ferritin) can take even longer.
Symptoms of acute iron overdose can include severe stomach pain, nausea, vomiting (sometimes with blood), diarrhea, dark or bloody stools, lethargy, and a weak, rapid pulse. In severe cases, it can lead to shock, liver failure, and even death. Accidental overdose in children is particularly dangerous. If you suspect an iron overdose, seek immediate emergency medical attention.
Iron supplementation is often recommended and safe during pregnancy, as iron requirements significantly increase to support the developing fetus and increased maternal blood volume. However, it should always be taken under the guidance of a healthcare provider, who can assess your iron levels and recommend an appropriate dose to prevent or treat iron deficiency anemia. (NIH ODS - Iron)
Interaction risk for Iron (ferrous bisglycinate) comes from the rest of the stack: other minerals, prescription medicines, hormone therapy and peptides. Because Iron (ferrous bisglycinate) is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Iron (ferrous bisglycinate) with no sign-up.
There is no single answer for Iron (ferrous bisglycinate) plus TRT. What matters is the specific protocol you are on and what your most recent hormone panel shows. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Pairing Iron (ferrous bisglycinate) with peptides has to be assessed one peptide at a time, because GLP-1 agonists, secretagogues, healing peptides and melanocortins do not share an interaction profile. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Iron (ferrous bisglycinate) varies by protocol and formulation, so the label or prescription is what sets it. It is typically taken in the morning. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Iron (ferrous bisglycinate) depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Iron (ferrous bisglycinate) the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
The weight of an iron salt is not the same as its elemental iron content. Compare the labeled elemental amount and formulation; do not compare products only by the larger chemical-compound weight.
No. Fatigue has many causes, and iron excess can be harmful. Blood tests and clinical assessment help distinguish deficiency from other problems; keep iron products away from children because accidental overdose can be fatal.
Ferrous bisglycinate trials pooled in the review used roughly 15-60 mg/day of elemental iron. Route reported: Oral tablets or capsules. Frequency reported: Once daily, or alternate-day dosing in some trials to limit hepcidin-driven blockade. These are amounts documented in the cited studies and labels for Iron (ferrous bisglycinate) — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
Which studies looked at Iron (ferrous bisglycinate)?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.The effects of oral ferrous bisglycinate supplementation on hemoglobin and ferritin concentrations in adults and children: a systematic review and meta-analysis of randomized controlled trials(opens PubMed in a new tab)Nutrition reviews · 2023 · PMID 36728680 · https://pubmed.ncbi.nlm.nih.gov/36728680/
- 2.Efficacy and Safety of Ferrous Bisglycinate and Folinic Acid in the Control of Iron Deficiency in Pregnant Women: A Randomized, Controlled Trial(opens PubMed in a new tab)Nutrients · 2022 · PMID 35276810 · https://pubmed.ncbi.nlm.nih.gov/35276810/
- 3.Effect of Low-Dose Iron Supplementation on Early Development in Breastfed Infants: A Randomized Clinical Trial(opens PubMed in a new tab)JAMA pediatrics · 2024 · PMID 38739382 · https://pubmed.ncbi.nlm.nih.gov/38739382/
- 4.Low-Dose Prophylactic Oral Iron Supplementation (Ferrous Fumarate, Ferrous Bisglycinate, and Ferrous Sulphate) in Pregnancy Is Not Associated With Clinically Significant Gastrointestinal Complaints: Results From Two Randomized Studies(opens PubMed in a new tab)Journal of pregnancy · 2024 · PMID 39582678 · https://pubmed.ncbi.nlm.nih.gov/39582678/
- 5.Daily versus Alternate-Day Iron Supplementation for Pregnant Women with Iron Deficiency Anemia: A Randomized Controlled Trial(opens PubMed in a new tab)American journal of perinatology · 2025 · PMID 39209303 · https://pubmed.ncbi.nlm.nih.gov/39209303/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- NIH Office of Dietary Supplements(opens in a new tab)National Institutes of Health · ods.od.nih.gov/factsheets/Iron-Consumer/
- PubChem CID 24393(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/24393
Verify at
Publisher search links for Iron (ferrous bisglycinate). These are places to check the information — they are not citations, so they are not numbered.
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Iron (ferrous bisglycinate)?
Plain-text summary, safe to quote verbatim:
Iron is an essential mineral vital for numerous bodily functions. Ferrous bisglycinate is a form of iron that is chelated to two glycine molecules. Research on Iron (ferrous bisglycinate) focuses on fertility, healthy aging, and women's healthspan. It is typically taken in the morning.
Source: DoseRoutine — https://doseroutine.com/library/iron
Iron (ferrous bisglycinate) cheat sheet
DoseRoutine cheat sheet · Mineral
Iron (ferrous bisglycinate)
Iron is an essential mineral vital for numerous bodily functions. Ferrous bisglycinate is a form of iron that is chelated to two glycine molecules.
Evidence
Moderate
Covered by a systematic review, without regulatory approval.
Studied range
Ferrous bisglycinate trials pooled in the review used roughly 15-60 mg/day of elemental iron
Route
Oral tablets or capsules
Frequency studied
Once daily, or alternate-day dosing in some trials to limit hepcidin-driven blockade
Half-life
Not applicable - iron is stored and recycled rather than cleared
Timing
in the morning
Storage
Cool, dry, sealed and out of reach of children
OTC supplementIron overdose is a leading cause of poisoning deaths in young childrenSupplementing without a documented deficiency risks iron overloadFertilityLongevityWomens Longevity
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/iron
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Iron (ferrous bisglycinate) — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/iron
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