Every day an adult should take in between 310 and 420 mg of magnesium1, but half the population doesn’t2,3. A small magnesium deficiency does not have immediate consequences, but in the long run it means you are slightly less healthy and have a slightly larger chance to get various diseases.

Consuming additional magnesium has been found to reduce the risk of heart problems and stroke, reduce anxiety, prevent migraines and having many other health benefits1,4,5,6,7,8.

Magnesium supplements

Magnesium supplements are cheap and unlikely to cause harm: excess magnesium is readily removed from your blood by your kidneys. The maximum advised safe dose is 350 mg/day via supplements, but that it probably much more than you need. Taking half of that is likely to be enough and puts you further on the safe side.

There are several kinds of magnesium supplements, containing magnesium in different forms. Supplements containing ‘magnesium oxide’ are the cheapest, but are not very effective: only about 4% of the magnesium from such supplements is absorbed by the body. Look for supplements containing ‘magnesium citrate’ or other magnesium compounds: the body is much better at absorbing magnesium from those compounds and those are thus preferred.

When taking a powder supplement, be aware that e.g. magnesium citrate contains around 15% Mg (the other 85% being the citrate), so 1 gram of the powder will contain around 150mg of the elemental Mg you want to supplement.


  1. Magnesium – Fact Sheet for Health Professionals
  2. U.S. Department of Agriculture
  3. Wikipedia – Magnesium
  4. Dietary magnesium intake and the risk of cardiovascular disease, type 2 diabetes, and all-cause mortality: a dose–response meta-analysis of prospective cohort studies
  5. Harvard Meta-Analysis Shows That More Magnesium Slashes Heart Risk By 30 Percent
  6. Circulating and dietary magnesium and risk of cardiovascular disease: a systematic review and meta-analysis of prospective studies
  7. Magnesium at
  8. Josh Mitteldorf on magnesium