What is the most absorbable form of magnesium?

Magnesium glycinate is the most consistently absorbable form in controlled studies, with bioavailability in the 50–80% range. It is chelated to the amino acid glycine, which acts as a transport carrier across the intestinal wall. Magnesium malate and citrate are also well-absorbed alternatives.

Is magnesium oxide worth taking?

Magnesium oxide has approximately 4% bioavailability in controlled absorption studies, meaning most of the dose is excreted without reaching the bloodstream. It is widely used in low-cost supplements because it contains a high percentage of elemental magnesium by weight, making label numbers look favorable. For therapeutic purposes, chelated forms such as glycinate or malate are significantly more effective.

Can I take magnesium glycinate and magnesium threonate together?

Yes. Glycinate and threonate serve different primary purposes — glycinate supports systemic magnesium repletion, while threonate is specifically designed to raise magnesium levels in the brain. Many practitioners use both forms concurrently without concern for interaction. Total daily intake across all forms should remain within established tolerable upper intake levels.

Moderate Evidence

Best Form of Magnesium: A Clinical Guide

Magnesium is involved in over 300 enzymatic reactions. Yet the form matters enormously: absorption may range from 4% (oxide) to over 80% (glycinate) depending on which salt you take. This guide ranks every commercially relevant form by verified bioavailability data so you can make an informed choice.

Updated 2026 · Reviewed by Dr. Brennan Commerford, D.C.

Bioavailability

~4%

Best For

N/A — cheap filler in low-quality supplements

Bioavailability is approximately 4% in controlled studies. Present mainly for its high elemental magnesium content on labels, not for absorption.

Frequently Asked Questions

What is the most absorbable form of magnesium?: Magnesium glycinate is the most consistently absorbable form in controlled studies, with bioavailability in the 50–80% range. It is chelated to the amino acid glycine, which acts as a transport carrier across the intestinal wall. Magnesium malate and citrate are also well-absorbed alternatives.
Is magnesium oxide worth taking?: Magnesium oxide has approximately 4% bioavailability in controlled absorption studies, meaning most of the dose is excreted without reaching the bloodstream. It is widely used in low-cost supplements because it contains a high percentage of elemental magnesium by weight, making label numbers look favorable. For therapeutic purposes, chelated forms such as glycinate or malate are significantly more effective.
Can I take magnesium glycinate and magnesium threonate together?: Yes. Glycinate and threonate serve different primary purposes — glycinate supports systemic magnesium repletion, while threonate is specifically designed to raise magnesium levels in the brain. Many practitioners use both forms concurrently without concern for interaction. Total daily intake across all forms should remain within established tolerable upper intake levels.

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FormulaForge formulates and sells supplements containing the ingredients discussed on this page. Our formulary recommendations are based on peer-reviewed bioavailability research. All cited studies are independently verifiable.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.