Supplement form

Iron Bisglycinate

Minerals A form of Iron 2 products in Stacky

Iron bound to two molecules of the amino acid glycine. Also sold as Ferrous Bisglycinate, Iron Glycinate. No authority has published an intake figure for iron bisglycinate itself. The figures further down are iron’s, and this page says what they count.

Stacky is an organisational tool, not a medical device. It does not provide medical advice, and nothing on this page says what iron bisglycinate does. Talk to a doctor or pharmacist before starting, stopping or changing what you take.

The number on the bottle and the number in the limit

Intake references for a mineral are set on the element. When EFSA writes 250 mg for magnesium, it means 250 milligrams of magnesium, the metal itself.

A supplement label can mean either of two things by a milligram. Some brands declare the iron delivered. Others declare the mass of the whole compound, iron plus whatever it is bound to. The iron is only a fraction of that weight, and the fraction is different for every salt.

FormIron by weight
Iron bisglycinate about 27%

Calculated from each compound’s anhydrous formula (Fe(C₂H₄NO₂)₂ for iron bisglycinate) using standard atomic weights. Real product is usually a little lower, because these salts are often sold hydrated. This is our arithmetic, not a regulator’s figure.

How to read your own label

A label that declares the element writes it like this. The figure is iron, and it is the number the references below are about.

Iron (as ferrous bisglycinate) ................ 25 mg

A label that names only the compound writes it like this. That figure is the whole salt, and the iron in it is about 27% of it.

Ferrous bisglycinate ........................... 90 mg

Stacky does not convert between the two. We do not know which salt, which hydrate or which convention your brand used, and a guess would turn a figure you can check into one you cannot.

Published intake references for iron, the element

These figures are iron’s. They are here because iron bisglycinate is a source of iron, not because any authority set them for iron bisglycinate. Where the EU and the US disagree, both are shown; nothing is averaged, converted or reconciled. A tolerable upper intake level is the only kind of figure that sets a ceiling; a recommended or adequate intake is context, not a limit.

Figures for Iron, reproduced from its own page
European Union — EFSA · Recommended daily intake (RDA / PRI) 11 mg of iron adult males 18+ EFSA →
European Union — EFSA · Recommended daily intake (RDA / PRI) 11 mg of iron postmenopausal adult females EFSA →
European Union — EFSA · Recommended daily intake (RDA / PRI) 16 mg of iron premenopausal adult females 18+ (PRI covers the requirement of approximately 95% of premenopausal women) EFSA →
European Union — EFSA · No upper limit established by this authority None established No EFSA UL established for iron - insufficient data to derive a UL (EFSA NDA Panel, 2024). EFSA instead published a 'safe level of intake'. EFSA →
United States — NIH ODS / IOM · Recommended daily intake (RDA / PRI) 8 mg of iron adult males 19+; adult females 51+ NIH ODS / IOM-DRI (NASEM) →
United States — NIH ODS / IOM · Recommended daily intake (RDA / PRI) 18 mg of iron adult females 19-50 NIH ODS / IOM-DRI (NASEM) →
United States — NIH ODS / IOM · Tolerable upper intake level 45 mg of iron adults 19+, total intake from all sources NIH ODS / IOM-DRI (NASEM) →

On the EU ceiling and this form. EFSA has published no upper limit for iron. The US figure of 45 mg is set on iron from all sources and carries no form note.

“None established” means that authority examined iron and set no figure.

Products in Stacky’s catalogue declaring iron bisglycinate

2 products whose label names iron bisglycinate as the form. Amounts are what the manufacturer prints, in whichever convention the manufacturer chose; the product page shows them as declared. No product here is recommended, ranked or endorsed.

Indexed studies

A study reaches this page only if its own title names iron bisglycinate or one of its recorded alternative names, and does not name a disease or clinical condition. Titles are the studies’ own words, newest first. A study appearing here is not a statement that iron bisglycinate does what the study set out to look at. How this list is built →

TitleJournalYearReference
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. Nutr Rev 2023 PubMed 36728680

Showing 1 of the 5 papers indexed against iron bisglycinate in Stacky.

About this page

What this page does not contain: a figure of its own for iron bisglycinate, a recommended dose, a grade, a conversion of any product’s amount, or any statement that it treats, prevents or improves a condition. How these pages are built →

Figures are read from the authorities’ published tables and can go out of date when those tables are revised. If one here is wrong, tell us at support@stacky-app.com and we will check it against the source.