Dietitian playing oz tag

Magnesium Supplementing to improve athletic performance: Fact or Fiction?

Written by Student Dietitian & OzTag Athlete – Madison Prendergast


Whether you’re an athlete, or just love your local social comp for football, we are always looking for a way to improve our performance to give us that competitive edge over our opponents. One component of our diet to consider is Magnesium (Mg), as it is extremely important for many functions in the body. It is needed in glucose metabolism, it’s a cofactor in many enzymes in the body and it’s also important in allowing our muscles to relax after contraction. BUT can this tiny micronutrient be the answer to improving athletic performance? And can it be an effective performance-enhancing supplement to improve overall athletic abilities?


Read below to find out…



Dietitian playing oz tag


In terms of athletic performance…


Despite the vast need for Mg in the body, there are very few studies confirming its correlation in supplementation within athletes to improved athletic performance. Overall, the weight of the evidence does not support supplementing Mg before events to improve athletic performance, prolong time to muscle fatigue, or reduce the time for muscle recovery. This is why the AIS has categorized Mg into group C, meaning that there is not enough evidence to show benefits among athletes, and supplementing is not advocated.


So why doesn’t more Mg = better for our muscles in performance?


Our body and our muscles will use what it needs and then excrete the rest.


Think of our body/muscles like a glass of water. Once the glass of water is full, water cannot be used anymore within the glass it will overflow onto the ground and be basically useless to the person who wants to drink it. This is just like Mg in the body. Once we have obtained enough Mg, just like the glass of water, the Mg will ‘overflow’, and in this case be excreted from the body.


However, there is evidence to suggest that athletes may actually have higher requirements for Mg due to higher muscle usage, however, due to the lack of evidence we cannot come to this conclusion, and RDI’s for the general population are still recommended.


Our advice


Meet your RDI and go from there..

The Recommended Daily Intake for females is 320mg/day and for men, 420mg/day.


Mg deficiency includes the following symptoms:

  • loss of appetite.
  • nausea/vomiting.
  • fatigue/weakness.
  • muscle spasms.
  • sleepiness

Whilst excessive Mg may result in:

  • nausea
  • diarrhea
  • muscle weakness
  • fatigue

By reaching your RDI and staying within that range, your body will be in a great position to perform to the best of its abilities.

Men's rugby

Quick Fact: One study suggested that 50% of Australian Female athletes were not reaching their RDI for Mg (3)! Who knows how this could have been affecting their performance!


Our body requires Mg regularly within the diet, and it can be found in a wide variety of foods, including:

  • Spinach and other leafy greens
  • Wholegrains e.g. Brown rice, quinoa
  • Avocado
  • Beans
  • Nuts
  • Seeds
  • Fish

There is no evidence to suggest that supplementing is better than food, and it is much more beneficial to overall health to gain your Mg through a food first approach! (And if you can’t reach it, look to supplementing under the guidance of your dietitian of course!).


If you feel as though you need guidance surrounding Mg and your diet, book in with your local dietitian! They will guide and educate you surrounding this topic, and any other nutrition questions you may have.






2. Chen, H.-Y., Cheng, F.-C., Pan, H.-C., Hsu, J.-C., & Wang, M.-F. (2014). Magnesium Enhances Exercise Performance via Increasing Glucose Availability in the Blood, Muscle, and Brain during Exercise. PLoS ONE, 9(1), e85486.


3. Heffernan SM, Horner K, De Vito G, Conway GE. The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review. Nutrients. 2019; 11(3):696.


4. Steward, C.J., Zhou, Y., Keane, G. et al. One week of magnesium supplementation lowers IL-6, muscle soreness and increases post-exercise blood glucose in response to downhill running. Eur J Appl Physiol 119, 2617–2627 (2019).


5. Zhang, Y., Xun, P., Wang, R., Mao, L., & He, K. (2017). Can magnesium enhance exercise performance? Nutrients, 9(9), 946. doi:

Similar Posts