victorem secondary logo teal

Unlocking Endurance: The Best Magnesium for Athletes

a males legs as he rides a bike on a concrete road

Magnesium is essential for endurance athlete health and performance. You may benefit from magnesium supplementation, but it can be confusing to know which kind is the best magnesium for athletes.

Do you ever struggle with low energy? Do you suffer muscle cramps? Do you have trouble sleeping?

These are possible signs of many conditions, but they could indicate that you are not getting enough magnesium in your diet. If so, it may be the missing piece to your performance puzzle. As an endurance athlete, you demand a lot from your body, and making sure you have the right magnesium supplement can make a difference in reaching your peak potential. 

Hi! As a sports dietitian and long-distance runner, I am here to help you learn how to get more magnesium through foods and supplements to support your endurance training and health.

In this blog, you will learn:

  • Roles of Magnesium
  • Food Sources
  • Daily Magnesium Needs
  • Types of Magnesium Supplements
  • Supplement Safety

First, let’s dive in (figuratively!) to the roles of magnesium and uncover the best magnesium for athletes like you.

Roles of Magnesium

Magnesium is a powerhouse for endurance athletes playing an important role in over 350 reactions in your body! It is also the fourth most abundant mineral in your body and some amount is lost in your sweat. (1)

Key Roles of Magnesium:

  • Energy production
  • Protein synthesis
  • Muscle contraction and relaxation
  • Normal heart rhythm
  • Bone structure
  • Glucose and insulin metabolism
  • Blood pressure regulation
  • Bowel function
  • Brain function and mood

{BONUS} Magnesium has a calming effect on the nervous system which may help you alleviate race day anxiety and gastrointestinal (GI) distress.

Not only that but magnesium may be beneficial for recovery and support mental health, both of which are important for total athlete health and performance. (2)

Sleep is an important component of recovery, and magnesium plays a role in promoting restful sleep by increasing melatonin and enhancing the effects of gamma-aminobutyric acid (GABA), a chemical messenger in your brain that has a calming effect. (3)

Daily magnesium intakes are less than ideal for most Americans, and you also lose more through sweat loss. This may increase your risk of deficiency or less than ideal levels, especially if you have a genetic tendency to underutilize magnesium.

A combined approach including whole foods and supplements may be a good option, but it is always a good idea to include whole food sources before taking a supplement.

Next, let’s discuss some of the best food sources of magnesium you can add into your daily diet.

Food Sources of Magnesium

As an endurance athlete, you demand a lot from your body and it can be difficult to keep track of every nutrient you need every single day to support your training. Do not overstress to reach perfection. Instead, aim to include some of these foods in your diet each day. In other words, try your best!
Magnesium can be found in both plant and animal foods, but plant foods are your best sources. (4)

graphic that outlines the top 10 foods for the best magnesium for athletes

There are many ways to incorporate more foods high in magnesium in your diet. 

Download 7 of my favorite magnesium-rich plant-based recipes if you want some ideas to boost your endurance training!

Only about 20-40% of magnesium from the food you eat is used in your body, however there are some things you can do to help with magnesium absorption.

How to Maximize Absorption

While magnesium absorption from food is relatively low, thankfully there are ways to boost–or blunt–magnesium absorption from foods and supplements.

  • Eat magnesium-rich foods throughout the day (rather than in one meal) and take smaller supplement doses to help increase absorption.
  • Calcium and magnesium can compete with each other so you may not want to combine high amounts of both in one meal. If you are supplementing with either of these, you may want to avoid taking these as a combined supplement. This also means you may not want to take a magnesium supplement with a glass of milk.
  • High doses of zinc–although generally not recommended–reduces magnesium absorption.(5)
  • Diuretics, antacids, caffeine, and alcohol can blunt magnesium absorption and should be consumed in moderation with magnesium-rich meals.

Next, let’s take a look at daily magnesium recommendations so you can get an idea if you are getting enough magnesium from the foods you consume regularly.

Daily Magnesium Needs

The current Recommended Dietary Allowance (RDA) for magnesium is 310-320 mg for women and 400-420 mg for men. The Tolerable Upper Limit (UL) is 350 mg from supplements and medications. (6)

Your body has unique needs and it is possible that you need more than the RDA for magnesium. Personalized nutrition is still in its infancy, but there are genetic testing options that can offer insight into your genetic tendency to have a below average, average, or above average blood magnesium level.

Low magnesium levels:

  • Impair efficiency of muscle contraction and relaxation leading to elevated lactic acid and poor muscle endurance. (7, 8
  • Affect your muscle strength and endurance due to reduced protein utilization. 
  • Are associated with an increased risk for diabetes which can contribute to other chronic diseases.

About 50-60% of magnesium in your body is stored in bone and only about 1% is found in your blood. Unfortunately, this means that monitoring your magnesium levels can be difficult. Red blood cell (RBC) magnesium is the preferred biomarker rather than serum or plasma levels. (9)

Although toxicity from food intake is rare, it is possible to have too much from supplementation. There are side effects you will want to avoid and too much or not enough may negatively impact your bone health.

Next, we will discuss the different types and individual benefits of various magnesium supplements.

pill bottle with a white label that says magnesium

Magnesium Supplements

When it comes to magnesium supplementation, it’s important to match the type with your specific needs. Some types can have a laxative effect which may not be the effect you prefer during training or a race (unless you’re racing to the porta potty!). 

Types of Magnesium Supplements

  • Chloride: Laxative effect, muscle health, stress
  • Citrate: Laxative effects
  • Glycinate (also called bisglycinate): sleep, muscle relaxation, headaches, stress; well-tolerated
  • L-Threonate: memory, cognitive function (10)
  • Malate: delayed onset muscle soreness (DOMs), pain & fatigue (11)
  • Oxide: Laxative effects
  • Taurate: cardiovascular health, anxiety, stress, insulin sensitivity, muscle cramps, headaches

If you’re aiming to avoid laxative effects, it may be best to steer clear of magnesium oxide, magnesium citrate, and magnesium chloride, as they may lead to unwanted GI issues. 

Instead, opt for a well-tolerated option like magnesium glycinate that supports performance and sleep quality (double bonus!). Among these, magnesium glycinate, also known as magnesium bisglycinate, is typically my top recommendation. However, L-threonate, malate, and taurate offer promising benefits with reported tolerability.

As an endurance athlete, you may need more than the RDA due to genetic tendency and increased loss in sweat, but use caution supplementing over 350 mg per day. Whichever form you choose to supplement, increase the dose slowly and practice around training instead of race day.

Now that you know what kind of magnesium supplement you may be looking to try, let’s discuss how to identify a safe supplement to further reduce your risk of unwanted GI distress along with other risks.

Supplement Safety

Choosing a supplement and reading the supplement label can be confusing. Supplements are not regulated the same way that foods are so you want to make sure that what you are buying is actually in the bottle (especially if it is a type of magnesium that has laxative effects!).

Also, supplements can be adulterated with steroids or banned substances. If you are drug tested for your race–or worried about taking steroids unintentionally–you will want to know what you are buying. 

The best way to know what you are buying and minimize your risk is to look for credible third-party testing certifications and buy from a reputable source.

Four ways to reduce your risk when choosing a supplement:

  1. NSF Certified for Sport
  2. Informed Sport
  3. USP Verified
  4. Professional-grade dispensary (Order from my affiliate dispensary for 20% off!)

Victorem is committed to educating you about benefits and risks of supplementing while also providing access to high-quality supplements. Schedule a consultation if you are not sure which type of supplement or how much you should take.

Finally, let’s review the key takeaways for magnesium.

Key Takeaways: Magnesium for Endurance

Magnesium supports health and endurance and it is possible that you are not getting enough in your diet. However, it can be challenging to determine the best magnesium for athletes and a combined approach including whole foods and supplementation is often most effective.

In summary:

  • Include magnesium-rich foods in your daily diet.
  • Choose a magnesium supplement based on the type that best meets your needs.
  • Use caution if supplementing over 350 mg magnesium per day.
  • Experiment with timing and dosing to optimize sleep quality, mental well-being, and performance.
  • Consider genetic testing to understand your individual magnesium tendency.
  • Prioritize quality and safety when choosing a supplement.

As a sports dietitian, I specialize in personalized nutrition recommendations tailored to your endurance training needs!  Schedule a consultation to begin your journey to better health and improved endurance performance.


More Posts

Send Us A Message

Jena Brown RD CSSD LD headshot

Meet Jena Brown

Jena founded Victorem Performance Nutrition to help endurance athletes define and achieve their own brand of victory. Over the course of 15 years, she has partnered with hundreds of athletes by leveraging data-informed custom nutrition plans and non-restrictive nutritional counseling.

Order supplements through my Fullscript store.