Form Comparison

Magnesium Chloride vs Magnesium Citrate

How magnesium chloride and magnesium citrate 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 chloride when you prefer a liquid or slow-release tablet. Choose magnesium citrate when you want proven absorption at the lowest cost and loose stools are not a problem.

Side by Side

Magnesium Chloride Magnesium Citrate
Elemental content 12% elemental magnesium 16.2% elemental magnesium
Absorption High High
How it is absorbed Highly soluble inorganic salt. Absorption was equivalent to lactate and aspartate and far above oxide in Firoz and Graber 2001. Highly soluble organic salt. Produced significantly higher serum and urinary magnesium than oxide in a randomized crossover trial (Kappeler 2017).
Typical dose 100-350 mg elemental magnesium daily 100-350 mg elemental magnesium daily
Common uses liquid supplements, slow-release tablets, electrolyte drinks general repletion, constipation, best value per absorbed mg
Side effects Bitter in liquid form. Slow-release tablets are well tolerated. Osmotic laxative effect becomes noticeable above roughly 200 mg elemental per dose.
Cost Moderate Low
Also called magnesium chloride hexahydrate trimagnesium citrate
Labels in index 58 1,343

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.

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When to Choose Magnesium Citrate

Choose magnesium citrate when you want proven absorption at the lowest cost and loose stools are not a problem. Hydrated or partially neutralized citrate powders can run 11-14% elemental rather than 16.2%. Citrate also alkalinizes urine, which is why it appears in kidney stone prevention.

Magnesium Citrate

The value choice for repletion. Proven absorption advantage over oxide at a low cost per absorbed milligram.

What to look for: Capsules or tablets stating elemental mg per serving. Expect looser stools above about 200 mg per dose.

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Products on Titrate

In Titrate's index of NIH label data, 58 labels in the Magnesium category list magnesium chloride and 1,343 list magnesium citrate.

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.