Does magnesium glycinate help with heart palpitations or afib? What the research does and doesn't show

The evidence doesn't support magnesium glycinate, or oral magnesium generally, as a treatment for heart palpitations or atrial fibrillation. The one placebo-controlled trial that tested oral magnesium against an actual heart-rhythm measurement in a general population found no difference from placebo, even though blood magnesium rose as expected.

What the evidence doesn't support

It doesn't support magnesium glycinate, or any oral magnesium supplement, as something that reduces heart palpitations, prevents atrial fibrillation, or treats any arrhythmia in someone taking it at home. The clearest positive signal for magnesium and heart rhythm in the research comes from a completely different setting — hospitalized, critically ill patients receiving supervised magnesium in an ICU — which doesn't tell you what an oral capsule does for an otherwise healthy person's occasional palpitations.

What the trials found

A 2018 double-blind pilot trial randomized 59 adults (mostly women, average age 62) to 400 mg/day of oral magnesium oxide or a matching placebo, and used a two-week wearable heart monitor (ZioPatch) to track premature atrial contractions — the kind of extra beats people often experience as palpitations. Blood magnesium rose significantly more in the magnesium group than placebo, confirming people actually took it. But there was no difference between the magnesium and placebo groups in the change in premature atrial contraction burden, blood glucose, or blood pressure. Gastrointestinal side effects were notably more common with magnesium (50% of participants) than placebo (7%). The trial was explicitly designed as a feasibility pilot for a larger study, but on its own primary rhythm measurement, it found nothing.

A 2022 study looked at a very different population: adult patients in intensive care. Using a statistical technique based on which nurses tended to give magnesium, researchers estimated that magnesium supplementation was associated with a small (3%) reduction in the relative risk of an atrial fibrillation event across more than 2,000 ICU admissions. This wasn't a randomized trial, and the authors' own background section says plainly that no randomized study supports this common ICU practice. It's also a completely different situation from taking a capsule at home: these are acutely ill, hospitalized patients with magnesium given and monitored by clinical staff, often to correct a documented deficiency, not a general-population supplement question.

Questions people ask

Can magnesium glycinate cause heart palpitations?

Neither trial above reported palpitations as a side effect of magnesium; the more commonly reported side effects were gastrointestinal. Very high magnesium intake, well above supplement doses, can affect heart rhythm through other mechanisms, which is a separate safety topic from ordinary supplementation.

Does magnesium glycinate help with heart palpitations?

The one placebo-controlled trial that directly measured this, using a heart-rhythm monitor, found no difference between magnesium and placebo on premature atrial contractions.

Can too much magnesium glycinate cause heart palpitations?

The trials reviewed here didn't test doses high enough to answer that. Magnesium toxicity affecting heart rhythm is documented at levels far above a standard oral supplement dose, and is a different question from ordinary daily use.

When to talk to a doctor

New, frequent, or severe heart palpitations, or any diagnosis of atrial fibrillation, need medical evaluation — an EKG or heart monitor can identify what's actually happening, which a supplement cannot. Magnesium is not a treatment for atrial fibrillation or any arrhythmia. If you take heart medication of any kind, ask your doctor before adding a magnesium supplement.

Related reading: magnesium glycinate and medications: what to check and how much magnesium glycinate is too much?.