Supplement Label Index

Magnesium Oxide vs. Magnesium Amino Acid Chelate

Among 6,062 on-market magnesium products with an identifiable primary form, 52.4% use Magnesium Oxide (3,177 products) and 4.6% use Magnesium Amino Acid Chelate (279).

Magnesium OxideMagnesium Amino Acid Chelate
Quality tierTier 3Tier 2
Magnesium by weight60.3%
Share of market52.4%4.6%
On-market products3,177279
Median declared dose100 elemental mg
middle half: 47.38–140
83 elemental mg
middle half: 25–175
Most common brandsDC, Wonder Laboratories, GNC Mega MenNaturesPlus, Douglas Laboratories, MH Michael's Health Naturopathic Programs

Doses are declared per serving in elemental mg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).

Why Magnesium Oxide is tier 3

Virtually insoluble in water, only ~43% soluble even under peak gastric acid.

Source: Lindberg JS et al. 1990, J Am Coll Nutr 9(1):48-55, PMID 2407766

Why Magnesium Amino Acid Chelate is tier 2

Lower urinary/salivary Mg response than citrate in one RCT, though "amino acid chelate" is not a single defined compound.

Source: Walker AF et al. 2003, PMID 14596323

Tiers summarize published comparative bioavailability or outcome evidence for each form (see methodology). This page describes the market; it is not a recommendation to take either form. Talk to a clinician about what's right for you.

Other magnesium comparisons