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Magnesium: what it really helps (and what it doesn’t)

By Caleb · July 8, 2026 · 5 min read

Magnesium is involved in hundreds of processes — muscles, nerves, blood sugar, sleep. It’s a genuinely important mineral, but it’s also over-hyped as a fix for everything. Here’s the honest picture.

Where the evidence is strongest

The best-supported use is migraine prevention, where magnesium has real evidence. Many people also find it helps sleep and muscle cramps, though the data there is softer. It is not a cure-all — benefits are clearest when you were low to begin with.

Why the blood test can mislead

A standard serum magnesium test is a weak indicator, because only about 1% of your body’s magnesium is in the blood — the rest is in bones and cells. A “normal” result doesn’t rule out low stores, so doctors weigh symptoms too.

Foods richest in magnesium

Food first is the safest route; supplements can cause loose stools and interact with medications.

Frequently asked questions

Does magnesium help you sleep?

Many people find it helps, but the evidence is modest and strongest if you were low. It’s reasonable to try food sources first and discuss supplements with your doctor.

Is a blood test reliable for magnesium?

Not very. Only about 1% of body magnesium is in the blood, so a normal serum test can miss low stores. Doctors interpret it alongside symptoms.

What foods are high in magnesium?

Pumpkin seeds, nuts, beans, lentils, whole grains, leafy greens and a little dark chocolate are all rich sources.

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This article is educational and not medical advice. Discuss supplements with your doctor, especially if you take medications or have kidney issues.