Form Comparison

Magnesium Aspartate vs Magnesium Glycinate

How magnesium aspartate and magnesium glycinate differ in elemental content, absorption, tolerance, and cost.

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Quick verdict. Both are rated high for absorption, and head-to-head human data do not reliably separate them. Choose magnesium aspartate when it comes in a formula you already want. It offers no distinct advantage over citrate. Choose magnesium glycinate when GI tolerance matters most or the dose is taken at bedtime.

Side by Side

Magnesium Aspartate Magnesium Glycinate
Elemental content Varies by product 14.1% elemental magnesium
Absorption High High
How it is absorbed Soluble organic salt. Absorption was equivalent to chloride and lactate in Firoz and Graber 2001. Magnesium bound to two glycine molecules. The chelate stays soluble across intestinal pH, and absorption proceeds through the same paracellular and TRPM6/7 channel routes as other soluble salts; head-to-head human data against citrate are limited.
Typical dose 100-350 mg elemental magnesium daily 100-350 mg elemental magnesium daily
Common uses general repletion, multi-mineral formulas general repletion, sleep support, sensitive stomachs
Side effects Mild osmotic effect at higher doses. The least likely form to cause loose stools at typical doses.
Cost Moderate Moderate
Also called magnesium L-aspartate magnesium bisglycinate, magnesium bisglycinate chelate, chelated magnesium
Labels in index 585 660

When to Choose Magnesium Aspartate

Choose magnesium aspartate when it comes in a formula you already want. It offers no distinct advantage over citrate. About 8.4% elemental as the anhydrous salt and lower as the hydrates sold commercially, so the panel figure is the one to use. Common in combination formulas with potassium aspartate.

Magnesium Aspartate

Choose magnesium aspartate when it comes in a formula you already want. It offers no distinct advantage over citrate.

What to look for: Magnesium Aspartate named on the Supplement Facts panel, with the amount per serving stated.

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When to Choose Magnesium Glycinate

Choose magnesium glycinate when GI tolerance matters most or the dose is taken at bedtime. 200 mg elemental magnesium as bisglycinate delivers roughly 1.2 g of glycine, which has its own small trials for subjective sleep quality. Buffered products blend in oxide to raise elemental content; check the panel.

Magnesium Glycinate

Best general-purpose form when tolerance matters. Well absorbed and the least likely to loosen stools.

What to look for: Bisglycinate as the only form on the panel (not buffered with oxide), with elemental mg per serving stated. USP or NSF verified.

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Products on Titrate

In Titrate's index of NIH label data, 585 labels in the Magnesium category list magnesium aspartate and 660 list magnesium glycinate.

Open supplement search

Supplement Search loads one category at a time. Choose the Magnesium tab, then type a form such as "bisglycinate" under Must contain, or a form to avoid under Must not contain.

Related

References

NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals.

Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001;14(4):257-262.

Kappeler D, et al. Higher bioavailability of magnesium citrate as compared to magnesium oxide shown by evaluation of urinary excretion and serum levels after single-dose administration in a randomized cross-over study. BMC Nutr. 2017;3:7.

Pardo MR, et al. Bioavailability of magnesium food supplements: A systematic review. Nutrition. 2021;89:111294.

Zhang X, et al. Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials. Hypertension. 2016;68(2):324-333.

Holland S, et al. Evidence-based guideline update: NSAIDs and other complementary treatments for episodic migraine prevention in adults. Neurology. 2012;78(17):1346-1353.

Garrison SR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9(9):CD009402.

Liu G, et al. Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. J Alzheimers Dis. 2016;49(4):971-990.