Magnesium for Muscle Recovery: What the Science Says (and Why Athletes Need More)

Ask a group of runners at the end of a Sunday long run what helps with cramps and sore legs, and someone will say magnesium. It has a reputation as the recovery mineral, the fix for night cramps and the key to better sleep.

Some of that reputation is earned and some of it is not. Here is what magnesium actually does, how much you need, and where the research stops supporting the hype.

Photo: SportPlus.sg / Isis Ang

Magnesium at a Glance

What Magnesium Does in Your Body

Magnesium is one of those minerals you rarely think about until someone tells you it is missing. A 2024 review in Cureus lists its main jobs:

• Energy: It is a cofactor for more than 300 enzyme reactions, including the ones that turn ATP into usable energy.
• Muscles and Nerves: It helps calcium channels work properly, which affects nerve signals and muscle relaxation.
• Repair: It is involved in protein synthesis, which your muscles rely on to repair after training.

A 2015 review on magnesium and athletes in Current Sports Medicine Reports adds that it helps maintain normal nerve and muscle function and heart rhythm, which is why it has been studied as a possible performance aid.

How Much Do You Need?

The recommended intake for adult men is 400 to 420mg a day, and for adult women 310 to 320mg a day. The 2024 review notes that requirements are higher for people with high physical activity levels.

Food comes first. Green leafy vegetables, whole grains, nuts, seeds and legumes are particularly rich sources. Sweat is only a minor route for losing magnesium; most leaves through your kidneys.

Some of magnesium's reputation is earned and some of it is not.

Where the Hype Runs Ahead of the Evidence

Cramps

A 2020 Cochrane review of 11 trials concluded that magnesium supplements are unlikely to provide meaningful protection against muscle cramps in older adults. For cramps during pregnancy the evidence is conflicting, and the reviewers found no trials at all on exercise-associated cramps.

Sleep

A 2023 systematic review found that observational studies link magnesium status with sleep quality, but randomised trials gave contradictory results. In other words, the trials have not settled whether taking magnesium improves sleep.

Side Effects

The same Cochrane review found oral magnesium was associated with mostly gut side effects, such as diarrhoea. Not ideal before a long run.

A Sensible Approach for Athletes

• Eat for It: Build meals around leafy greens, whole grains, nuts, seeds and beans.
• Test Before You Supplement: If you suspect you are low, ask your doctor about a blood test rather than guessing.
• Do Not Count on It for Cramps: There is no trial evidence for magnesium and exercise cramps, so talk to a coach or physio about what else might be going on.

Wind Down with AporeNaturals on ATHLO+

A massage at the end of the day is a good habit in its own right. AporeNaturals Magnesium Cream is made with 20% magnesium chloride and is described by AporeNaturals as 100% natural, vegan and non-toxic, and suitable for daily use, even on sensitive skin. Whether magnesium is absorbed through the skin is still unproven, so think of it as part of your evening wind-down rather than a supplement. Our guide to topical vs oral magnesium explains the difference, and you can find the full range on the AporeNaturals page.

Ready to compare creams and tablets? Read Topical vs Oral Magnesium next.