Supplement Label Index

Magnesium Citrate vs. Magnesium Aspartate

Among 6,062 on-market magnesium products with an identifiable primary form, 25.3% use Magnesium Citrate (1,533 products) and 8.2% use Magnesium Aspartate (500).

Magnesium CitrateMagnesium Aspartate
Quality tierTier 1Unrated
Magnesium by weight16.2%8.4%
Share of market25.3%8.2%
On-market products1,533500
Median declared dose75 elemental mg
middle half: 24–150
76 elemental mg
middle half: 40–167.5
Most common brandsPure Encapsulations, Ultima, Douglas LaboratoriesBluebonnet, Douglas Laboratories, PS ProSupps

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 Citrate is tier 1

Far more soluble than oxide across physiological pH; produced the highest urinary/salivary Mg response of forms tested in a human RCT.

Source: Lindberg 1990, PMID 2407766; Walker AF et al. 2003, Magnesium Research 16(3):183-191, PMID 14596323

Why Magnesium Aspartate is unrated

No head-to-head human bioavailability study specific to this salt was found.

Source: uncertain -- needs review

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