Why we need magnesium

Are you ALWAYS sore after hard workouts?

Do you feel completely knocked down by stress?

What about sleep?

If you can’t remember the last time you had a restful night of sleep, it’s a good chance you’re not getting enough magnesium.

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Why is it important?

  • Magnesium is the 4th most abundant mineral in the body [R]. It is required for more than 300 different bodily processes [R]. It plays a huge role in your immune system, nerves, and muscles, and helps keep your heart and bones strong.

  • It’s involved in the synthesis of fat and protein, neurological activity, hormone production, muscular contraction and relaxation, cardiac activity and bone metabolism.

  • Even more important is magnesium’s role in both anaerobic and aerobic energy production, particularly in the metabolism of adenosine triphosphate (ATP), the 'energy currency' of the body.

Athletic Performance and Magnesium

  • Better Strength: without magnesium, the enzymes that enable muscle protein synthesis are weakened, compromising recovery, hypertrophy, and strength.

Regular strength training / HIIT increases the requirement of magnesium.

  • Hormone Balance: Healthy testosterone and balanced cortisol levels play a huge role in your performance. Magnesium helps maintain this equilibrium by helping to free up testosterone so that it can work its magic in the body. It also allows for the metabolism of cortisol after your workouts by reducing nervous system activation.

  • Better body composition and insulin sensitivity: It helps your body metabolise carbs and control blood glucose levels. A good level of magnesium creates a metabolic environment that will help you get higher muscle development and a leaner body composition in less time.

  • Recovery and sleep: Getting enough magnesium can accelerate recovery processes and aid sleep. Magnesium fights inflammation, raises antioxidant levels, and helps replenish energy stores in the muscle. It also calms the central nervous system, lowering heart rate and enabling restful sleep.

Magnesium plays a role in physical performance and muscle function, meaning that athletes and serious trainees are commonly deficient because strength training increases magnesium requirements.

Symptoms of Magnesium Deficiency

Magnesium is the second most common deficiency in the world after vitamin D deficiency. Whilst magnesium is not an ergogenic aid, correcting and guarding against deficiencies should assist performance on a number of levels.

The symptoms are mild enough to sometimes go unnoticed, and a lot of them can be attributed to straining our body and pushing it to work harder.

These are the most common:

  • Achy joints

  • Muscle cramps and twitching

  • Soreness

  • Lack of energy

  • Longer recovery time


Where do we get it from?

  • Beans and legumes

  • Dark leafy greens

  • Nuts and seeds (almonds, sesame seeds, cashews, pumpkin seeds, and flaxseed)

  • Tofu

  • Seafood

  • Red meat

  • Bananas

  • Dark Chocolate

  • Whole grains (especially quinoa, buckwheat, brown rice)

  • Potatoes

Supplementation and testing

Magnesium is primarily absorbed through the gut [R]. However, the kidneys are the main regulator of magnesium levels and activity throughout the body [RRR]. They tell the digestive system to absorb more or less magnesium from digested food according to the body’s current levels [RRR].

Because only 1% of total magnesium in the body is located outside of cells, blood levels do not reflect magnesium levels inside of cells. Red Blood Cell magnesium is a more accurate measurement of magnesium levels inside of cells and a better representation of total magnesium stores in the body [RRR].

Reference ranges for magnesium

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The biggest issue with magnesium is that it’s a little difficult to get your recommended daily intake through diet alone. That’s why we may need to add in supplementation.

There are several types of supplement you can take and it’s important to know the difference between them.

Here are the better options and how they’re believed to affect your health.

  • Magnesium L-Threonate – Supports cognitive function. Able to cross the blood brain barrier and most commonly used for brain health. Research has found it improves working memory and learning ability.

  • Magnesium Malate – Supports energy production.

  • Magnesium Taurate – Supports calmness and heart health.

  • Magnesium Bisglycinate – Supports relaxation.

  • Magnesium Orotate – Supports heart health.

  • Magnesium Aspartate – Supports energy production and fights fatigue.

Potential Adverse Effects

  • Excess amounts may cause GI distress.

  • All minerals compete for absorption. If high dose magnesium is taken, a broad-spectrum multi-mineral formula is advised.

Simply taking magnesium tablets daily can easily help you restore optimal levels of this mineral in your blood. As long as you are consistent with the consumption you’ll have nothing to worry about and you can get your energy levels back. During intense periods of training you can use epsom salt baths to ease muscle soreness and boost magnesium levels.

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Magnesium bisglycinate


Magnesium citrate


Epsom salt bath flakes

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Marta Lesina is one of our nutrition coaches based out of The Yard in Peckham and CrossFit Blackfriars. If you are interested in working with her head over to the nutrition coaching page and sign up for online coaching!


+ References / further reading

Nutrition adviceMarta Lesina