Iron bisglycinate
Iron is essential for carrying oxygen in the blood.
Fe(C₂H₄NO₂)₂
14–25 mg of elemental iron on alternate days.
What it is
Its deficiency is the most common nutritional deficiency in the world, especially in women who menstruate and on vegan diets. Tiredness from low iron appears before anaemia is diagnosed. The bisglycinate form usually causes less digestive discomfort than ferrous sulphate.
What the evidence says
Consistent trials and reviews in people, or health claims authorised in the EU.
Authorised EU claim Iron contributes to normal formation of red blood cells and haemoglobin and to the reduction of tiredness and fatigue. It only makes sense if a blood test confirms that yours is low.
| Year | What was studied | What was found | Source |
|---|---|---|---|
| 2012 | Fatigue with low ferritin, without anaemia | RCT in 198 women with tiredness and low ferritin but no anaemia: iron reduced fatigue significantly. | Vaucher et al.CMAJ |
| 2009 | Energy and mood | RCT in female soldiers during basic training: iron slowed the fall in their iron stores and improved their sense of vigour. Running time only improved in those who started with iron-deficiency anaemia. | McClung et al.American Journal of Clinical Nutrition |
| 2023 | The dose matters too | RCT in 480 Cambodian women, most without deficiency: 18 mg of bisglycinate raised ferritin less than 60 mg of ferrous sulphate, and there were no differences in markers of gut inflammation. A low dose of a well-absorbed form does not always match a higher dose. | Fischer et al.Journal of Nutrition |
What to look for on the label
- Ferrous bisglycinate.
- Taking it on alternate days improves absorption.
Precautions
- Only take it if a blood test confirms low iron or ferritin, and repeat the test after 3 months.
- If you have haemochromatosis or iron overload, do not take it.
- Keep it 4 hours apart from levothyroxine and 2 hours apart from antibiotics (tetracyclines, quinolones).
- Keep it out of the reach of children: an iron overdose is serious for them.
- It can cause constipation.
Where to find it
Products whose label meets what this profile asks for: form, dose per serving and nothing that contradicts it. Three at most: quality of the active comes first and, among the best, we look for one option in each price range. We choose by composition, not by who pays. The shops are European or ship to Europe.
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HSNShips from SpainEssential Series
Iron bisglycinate 20 mg
20 mg of iron per capsule
For the reference dose1 capsule, on alternate daysView at HSN (opens in a new tab)Meets the criteria.
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ThorneShips from the US: check delivery and customsThorne
Iron Bisglycinate
25 mg of iron per capsule
For the reference dose1 capsule, on alternate daysView at Thorne (opens in a new tab)Meets the criteria.
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NaturitasShips from SpainSolgar
Gentle Iron (bisglycinate)
20 mg of iron (Ferrochel®) per capsule
For the reference dose1 capsule, on alternate daysView at Naturitas (opens in a new tab)Meets the criteria.
We link to the shop; we do not sell anything. Today we earn no commission on any link. If we ever do, the link will say so and the selection will not change: the label decides. Labels checked on 2 November 2026; check the one on the pack before you buy. All these shops deliver to the EU; some of their pages open in Spanish. How we are funded.
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Profile reviewed on 3 November 2026. Sources: EFSA, Regulation (EU) 432/2012 and published studies. Image: Design for a chemical laboratory. Etching by A.W. Warren, 1822. Wellcome Collection, public domain.
General information based on published scientific evidence and EU law. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle, and are not intended to diagnose, treat or prevent any disease.
Do not exceed the daily dose stated on each product. If you take medication, have a medical condition or have any doubts, ask your doctor or pharmacist.