Magnesium

magnesium · magnesium glycinate · magnesium citrate · magnesium threonate

An essential mineral widely supplemented for sleep, muscle, mood and heart health.

TypeSupplement / dietary

The grade answers: What does the human evidence support for: Deficiency correction, sleep & metabolic support?

Grade

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class: Essential mineral
Primary use: Deficiency correction, sleep & metabolic support
Evidence strength: medium
Last reviewed: 2026-07-01

Bottom line

Correcting a real shortfall is worthwhile and many people under-consume it — but magnesium is not a longevity intervention, and 'more' past sufficiency doesn't help. Fix a deficiency, don't chase a miracle.

What the evidence says

Magnesium is genuinely essential for hundreds of enzymatic reactions, and a meaningful share of people don't hit recommended intakes. Supplementation has modest, reasonably supported benefits for sleep quality, blood pressure and possibly muscle cramps, particularly in those who are low. What it is not is a proven longevity or disease-prevention pill for the already-sufficient. Grade C: real value in correcting a shortfall, oversold as a cure-all.

Key studies

[1]
Magnesium supplementation and blood pressure · meta-analysis
Small reductions, larger in deficient/hypertensive people.
Open on PubMed ↗
[2]
Magnesium and sleep quality · review
Modest, inconsistent benefit; better evidence in the deficient.
Open on PubMed ↗
[3]
Magnesium status and health outcomes (review) · review
Deficiency matters; supraphysiologic dosing does not add benefit.
Open on PubMed ↗

See all studies on PubMed ↗

Scoped PubMed search, not a curated bibliography: the individual PMIDs for this entry have not yet been verified one by one. For that reason it is not used to support a high grade and is awaiting review.

Mechanism

A cofactor in ATP metabolism, DNA/protein synthesis, nerve and muscle function, and vascular tone; low status disrupts many of these processes.

Safety

Safe from food and at typical supplement doses. Excess supplemental magnesium (especially oxide) commonly causes diarrhoea; very high intake is risky in kidney impairment. Different salts differ mainly in absorption and laxative effect, not magic.

Dosage context

Typical supplemental doses are ~200–400 mg elemental magnesium/day. Glycinate/citrate are better tolerated than oxide; 'threonate' is marketed for the brain on limited human data.

Examples of application

Taken as glycinate/citrate (~200–400 mg elemental), often in the evening.
Aimed at correcting a real shortfall, not mega-dosing.
Oxide is cheap but poorly absorbed and more laxative.

From the field

Magnesium is a case where the boring advice is the right advice: many people are genuinely low, correcting that helps a bit, and beyond sufficiency there's nothing to chase. C, not a longevity headline.

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