Mineral
Iron (as Fermented Iron Bisglycinate)
Also known as: iron bisglycinate, fermented iron, chelated iron
Iron is an essential mineral critical for oxygen transport and fetal development during pregnancy. The bisglycinate chelate form offers enhanced absorption and bioavailability with reduced GI irritation compared to ferrous salts.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Iron (as Fermented Iron Bisglycinate) product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Thorne Iron Bisglycinate | 96 A | $0.27 |
| 2 | Transparent Labs Grass-Fed Whey Protein Isolate | 95 A | $2.00 |
| 3 | Complement ForHer Hormone Balance and Longevity Multivitamin for Women | 89 A | $0.67 |
| 4 | Thorne Basic Prenatal | 88 A | $1.23 |
| 5 | Ritual Essential Prenatal | 88 A | $0.65 |
| 6 | Pure Encapsulations Iron-C | 87 A | $0.32 |
| 7 | Solgar Gentle Iron | 87 A | $0.09 |
| 8 | Transparent Labs Multivitamin | 86 A- | $1.33 |
| 9 | Complement Restore | 86 A- | $1.90 |
| 10 | Seed AM-02™ Energy + Focus Supplement | 86 A- | $1.17 |
| 11 | Garden of Life Primal Defense Ultra | 86 A- | $0.56 |
| 12 | Garden of Life Organics Prenatal Multi | 86 A- | $1.14 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Iron (as Fermented Iron Bisglycinate) should I take?
The typical range is 27 mg daily (RDA for pregnant women). throughout pregnancy and postpartum; continue if breastfeeding
When should I take Iron (as Fermented Iron Bisglycinate)?
morning on empty stomach preferred for absorption, but can take with food if GI upset occurs. separate from calcium, zinc, and polyphenols by 2 hours when possible; vitamin C enhances absorption.
Which form of Iron (as Fermented Iron Bisglycinate) is best?
iron bisglycinate. Other forms in the catalog: ferrous fumarate, ferrous sulfate.
Is Iron (as Fermented Iron Bisglycinate) safe?
Commonly reported: constipation, nausea, dark stools.
Which Iron (as Fermented Iron Bisglycinate) supplement scores highest?
Thorne Iron Bisglycinate, at 96/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Oxygen transport
- Prevention of gestational anemia
- Fetal development and birth weight support
- Energy metabolism
How it works
- Component of hemoglobin and myoglobin
- Cofactor for iron-dependent enzymes
- Chelation improves intestinal absorption
- Reduced ionic irritation to GI tract
Dosage
- Typical range
- 27 mg daily (RDA for pregnant women)
- Timing
- morning on empty stomach preferred for absorption, but can take with food if GI upset occurs
- With food
- separate from calcium, zinc, and polyphenols by 2 hours when possible; vitamin C enhances absorption
- Duration
- throughout pregnancy and postpartum; continue if breastfeeding
- Special populations
- Pregnant women 27 mg/day; lactating women 9–10 mg/day; dosage may increase if anemia confirmed
Forms
- iron bisglycinate· 70/100
- ferrous fumarate· 70/100
- ferrous sulfate· 70/100
Safety
Common side effects
- constipation
- nausea
- dark stools
Contraindications
- Hemochromatosis
- sickle cell disease without supplementation indication
Products containing Iron (as Fermented Iron Bisglycinate)
Top-scoring supplements in our catalog that list Iron (as Fermented Iron Bisglycinate) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Extensive RCT evidence for iron supplementation in pregnancy; strong evidence that adequate iron prevents anemia and poor birth outcomes; chelated forms reduce side effects while maintaining efficacy.
Grade A: Multiple well-designed human trials support the main claims.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.