SUPPLEMENTSHORTLIST

Magnesium: forms, amounts and sleep claims

The short answer

Citrate, oxide and glycinate are different forms of magnesium. Check the form and the magnesium amount per serving on the label. A sleep claim needs evidence beyond those label details.

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Where do you get magnesium?

Magnesium supports muscle and nerve function and helps build protein and bone. Nuts, seeds, beans, whole grains and leafy vegetables are food sources.

Sources: NIH: Magnesium

Citrate, oxide, glycinate: what changes?

NIH reports that citrate, chloride, lactate and aspartate tend to be absorbed more readily than oxide and sulfate. Better absorption by itself does not establish better sleep or relief from a symptom.

Magnesium glycinate combines magnesium with glycine, an amino acid. It’s the form on our shortlist. The NIH absorption comparison above does not show that glycinate is better than the others.

Sources: NIH: Magnesium forms and amounts · PubChem: What glycinate is

Compare the magnesium, not the compound’s weight

The Supplement Facts panel lists elemental magnesium: the magnesium itself, without the rest of the compound. Use that amount and the full serving size to compare labels.

A made-up label example

Magnesium 200 mg · serving size: 2 capsules

The full two-capsule serving provides 200 mg of magnesium. This illustrates a label, not a personal dose recommendation.

How to read the Supplement Facts panel

Sources: NIH: Magnesium forms and amounts

What about sleep?

NCCIH says there isn’t enough rigorous evidence to establish that magnesium supplements treat insomnia or other sleep disorders. Some studies suggest a benefit, but small studies and mixed results leave the answer uncertain.

A bedtime label alone cannot show that a product will improve sleep. Talk with a health professional about sleep problems that persist.

Sources: NIH: Magnesium and sleep

Check medicines and other sources

Some antacids and laxatives contain magnesium too. Supplements can cause diarrhea, nausea or cramping and can interfere with medicines, including certain antibiotics. A pharmacist can check interactions and timing.

Kidney disease increases the risk from excess magnesium. Ask your clinician before adding it when you have impaired kidney function.

Sources: NIH: Magnesium · NIH: Magnesium forms and amounts

Take a closer look

Browse magnesiumSee the products and their labelsWhat does an electrolyte drink add?Before you take a supplement

Sources

  1. NIH Office of Dietary Supplements: Magnesium (opens in a new tab)
  2. NIH Office of Dietary Supplements: Magnesium — Health Professional Fact Sheet (opens in a new tab)
  3. NIH NCCIH: Magnesium Supplements for Sleep Disorders (opens in a new tab)
  4. NIH PubChem: Magnesium Glycinate — Compound 84645 (opens in a new tab)