Magnesium

Magnesium supplementation · Magnesium supplement · Mg supplementation

Snapshot

Indications	Contraindications
Hypomagnesemia¹ Blood pressure² Migraine prevention¹ Muscle soreness³ Sleep quality^4–7 Chronic constipation⁸	Impaired renal function¹ Soy-containing products⁹

Magnesium is an essential mineral and a cofactor in enzyme systems that govern muscle and nerve function, glucose control, and blood pressure¹. Supplementation is used to correct low intake or status, and for blood pressure, migraine prevention, sleep, and muscle soreness¹. Older adults, people with type 2 diabetes or alcohol dependence, and those with chronic gastrointestinal disease or on loop and thiazide diuretics are most prone to inadequacy¹.

A 2025 meta-analysis of randomized trials found modest blood pressure reductions, larger in hypertensive patients on medication and in hypomagnesemia². The American Academy of Neurology and American Headache Society judged magnesium probably effective for migraine prevention¹. Sleep trials are contradictory, while a systematic review in physically active people reported less muscle soreness. In a 2026 population-based cohort analysis, supplement users had more night cramps, and supplementation did not prevent them¹⁰. Products listing magnesium are mostly oxide, citrate, and chloride, with absorption differing by form; see Form comparison¹.

Renal impairment matters because the kidneys clear excess magnesium, so toxicity risk rises when that capacity falls¹. A 12-month trial in predialysis chronic kidney disease found more gastrointestinal and serious adverse events with magnesium¹¹. Per the National Institutes of Health (NIH) fact sheet, migraine-range intake exceeds the upper intake level and is used under health care provider supervision¹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

68 sources, 49 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Articles

Magnesium glycinate for sleep: the trial and 125 labelsOct 8, 2026One placebo-controlled trial found a small benefit at 250 mg of magnesium a night. Of 125 products, 42% reach that dose in one serving and none state their glycine.

Snapshot

In the full monograph

Articles

Sources