Key takeaways
Jump to a section
Compare magnesium food sources and supplement amounts, then read the authorised wording and cited reviews in context. This guide separates those sources from claims about sleep or exercise-related cramps.
What the magnesium claims cover
The exact EU-authorised wording for magnesium is shown in the box below.
There is no authorised EU health claim saying that magnesium builds muscle, speeds up fat loss, or improves performance beyond normal needs.
Magnesium and muscle cramps
The exact EU-authorised wording for magnesium is shown in the box above. A 2020 Cochrane review (Garrison et al.) concluded that it is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps, and found no randomised controlled trials evaluating magnesium for exercise-associated muscle cramps.
Magnesium, sleep and recovery
A 2023 systematic review (Arab et al.) reported that observational studies suggested an association between magnesium status and sleep quality, while the randomised controlled trials reported contradictory findings. Our rest and recovery guide covers sleep routine and training load. Our sister brand CapyOnsen built its three-step evening ritual around a wind-down routine, if you want a starting point.
How much magnesium do you need?
The NHS says that adults aged 19 to 64 need 300mg of magnesium a day (men) or 270mg a day (women), and lists spinach, nuts and wholemeal bread among the foods that contain it. Other foods often listed as sources:
- Leafy green vegetables (spinach, chard)
- Nuts and seeds (pumpkin seeds, almonds, cashews)
- Legumes (beans, lentils, chickpeas)
- Whole grains (oats, brown rice, wholemeal bread)
- Dark chocolate
The NHS says that you should be able to get all the magnesium you need by eating a varied and balanced diet, that taking high doses of magnesium (more than 400mg) for a short time can cause diarrhoea, and that having 400mg or less a day of magnesium from supplements is unlikely to cause any harm.
Forms of magnesium: glycinate vs citrate vs oxide
Magnesium supplements are sold in several forms. The label states the amount of elemental magnesium per serving:
- Magnesium glycinate (bisglycinate) — magnesium bound to the amino acid glycine.
- Magnesium citrate — a salt of magnesium and citric acid.
- Magnesium oxide — magnesium combined with oxygen.
Compare the elemental magnesium per serving and the price per serving.
Magnesium and other supplements
See our guide to the best supplements for muscle gain, where creatine and protein have their own EU-authorised claims, shown in the boxes on those pages.
Related: Best supplements for muscle gain · Creatine guide · Rest & recovery · Recovery nutrition basics.
Frequently asked questions
Is magnesium good for athletes?
The exact EU-authorised wording is shown in the box on this page. There is no authorised EU health claim saying that magnesium builds muscle, speeds up fat loss, or improves performance beyond normal needs.
Does magnesium stop muscle cramps?
The exact EU-authorised wording is shown in the box on this page. A 2020 Cochrane review (Garrison et al.) concluded that it is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps, and found no randomised controlled trials evaluating magnesium for exercise-associated muscle cramps.
How much magnesium should I take a day?
The NHS says that adults aged 19 to 64 need 300mg of magnesium a day (men) or 270mg a day (women), that taking high doses of magnesium (more than 400mg) for a short time can cause diarrhoea, and that having 400mg or less a day of magnesium from supplements is unlikely to cause any harm.
Which form of magnesium is best?
Magnesium supplements are sold as glycinate (magnesium bound to the amino acid glycine), citrate (a salt of magnesium and citric acid), oxide (magnesium combined with oxygen) and other forms. Compare the elemental magnesium per serving and the price per serving.