Form Comparison

Magnesium Aspartate vs Magnesium Chloride

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

This page contains affiliate links. Titrate earns a small commission when you purchase through them, at no cost to you. This does not affect our recommendations.

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 chloride when you prefer a liquid or slow-release tablet.

Side by Side

Magnesium Aspartate Magnesium Chloride
Elemental content Varies by product 12% elemental magnesium
Absorption High High
How it is absorbed Soluble organic salt. Absorption was equivalent to chloride and lactate in Firoz and Graber 2001. Highly soluble inorganic salt. Absorption was equivalent to lactate and aspartate and far above oxide in Firoz and Graber 2001.
Typical dose 100-350 mg elemental magnesium daily 100-350 mg elemental magnesium daily
Common uses general repletion, multi-mineral formulas liquid supplements, slow-release tablets, electrolyte drinks
Side effects Mild osmotic effect at higher doses. Bitter in liquid form. Slow-release tablets are well tolerated.
Cost Moderate Moderate
Also called magnesium L-aspartate magnesium chloride hexahydrate
Labels in index 585 58

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.

Find on iHerb Affiliate link

When to Choose Magnesium Chloride

Choose magnesium chloride when you prefer a liquid or slow-release tablet. Topical magnesium oil is chloride; transdermal absorption is not established.

Magnesium Chloride

Choose magnesium chloride when you prefer a liquid or slow-release tablet.

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

Find on iHerb Affiliate link

Products on Titrate

In Titrate's index of NIH label data, 585 labels in the Magnesium category list magnesium aspartate and 58 list magnesium chloride.

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.