Do athletes deplete magnesium? The truth about athletic mineral loss

October 8, 2025 •

4 min read

Studies have shown that athletes can lose up to 20% more magnesium through sweat and urine during training compared to sedentary individuals. This significant depletion highlights a critical consideration for sports nutritionists and athletes alike: do athletes deplete magnesium, and what does this mean for training, performance, and recovery?

Quick Summary

Athletes are susceptible to magnesium depletion due to increased losses from sweat and urine during strenuous exercise. This mineral is vital for energy production, muscle function, and recovery. Maintaining adequate levels is essential to prevent cramps and fatigue, ensuring optimal athletic performance and health.

Key Points

Depletion Risk: Athletes face a higher risk of magnesium depletion due to increased losses through sweat and urine during intense exercise.
Vital Function: Magnesium is essential for energy production, muscle contraction, and nerve function, all critical for peak athletic performance.
Signs of Deficiency: Common symptoms include muscle cramps, fatigue, slower recovery, and poor sleep quality, all of which can hinder training.
Dietary Focus: A diet rich in leafy greens, nuts, seeds, whole grains, and legumes is the best defense against depletion.
Strategic Supplementation: When diet isn't enough, selecting a highly bioavailable supplement like magnesium glycinate or citrate can be an effective strategy.
Consistency is Key: For building up magnesium stores, regular, daily intake is more effective than one-off or occasional dosing, especially around competitions.

The Foundation of Magnesium: Why It's Crucial for Performance

Magnesium is a cornerstone of human physiology, serving as a cofactor for over 300 enzymatic reactions in the body. For athletes, its importance is magnified by the physical stress of training and competition. It's involved in everything from energy production and protein synthesis to muscle function and nerve transmission. During exercise, these processes accelerate, placing a greater demand on the body's mineral stores. An optimal magnesium balance is key to ensuring that the body can meet these heightened metabolic needs.

The Mechanisms Behind Magnesium Depletion in Athletes

While many people don't meet the recommended daily intake of magnesium, athletes face additional factors that increase their risk of deficiency.

Increased Losses Through Sweat: When athletes engage in intense or prolonged exercise, they lose significant electrolytes through sweating, and magnesium is among them. While the total amount lost in sweat per hour is relatively small, consistent, heavy sweating over a training season can lead to a notable net loss.
Higher Urinary Excretion: Research indicates that athletes experience increased magnesium excretion via urine, even with higher dietary intake compared to non-athletes. This suggests that exercise influences the kidneys' handling of magnesium, leading to greater losses during and after training.
Elevated Metabolic Demand: The process of converting food into energy (ATP) relies heavily on magnesium. Athletes in high-intensity sports have higher energy turnover, further increasing their body's utilization of this mineral. This can exhaust magnesium reserves if not adequately replaced through diet.
Restrictive Diets: Athletes in weight-sensitive sports, such as endurance running or gymnastics, may follow restrictive diets to maintain a certain weight. These diets can often be low in magnesium-rich whole grains, nuts, and seeds, putting them at higher risk for low intake.

The Impact of Low Magnesium Status on Athletes

Suboptimal magnesium levels can manifest in various ways, directly affecting an athlete's health and performance. Recognizing these symptoms is the first step toward correcting the imbalance.

Muscle Cramps and Spasms: One of the most well-known signs of low magnesium is involuntary muscle contractions, cramps, and twitching. This is because magnesium helps to relax muscles, acting as a natural calcium blocker. A deficiency disrupts this balance, leading to uncontrolled contractions.
Fatigue and Low Energy: Since magnesium is critical for ATP production, its deficiency can impair the body's energy-generating capacity, leading to persistent fatigue and reduced endurance.
Impaired Recovery: Magnesium aids in muscle recovery by reducing inflammation and promoting tissue repair. Lower levels can result in slower recovery times and increased muscle soreness after intense workouts.
Poor Sleep Quality: Magnesium has a calming effect on the nervous system and is involved in regulating the sleep-wake cycle. Inadequate levels can lead to restless sleep, further hindering recovery.
Increased Injury Risk: Chronic low magnesium status can negatively affect bone metabolism, potentially increasing the risk of stress fractures and other bone-related injuries. Low levels can also impair muscle and nerve function, making athletes more susceptible to strains.

Strategic Approaches to Magnesium Repletion

Athletes can take a proactive approach to prevent and correct magnesium depletion by focusing on both diet and, if necessary, supplementation.

Dietary Strategies for Boosting Magnesium

For most athletes, optimizing dietary intake is the primary and most sustainable solution. A balanced diet rich in whole foods is essential.

Seeds: Pumpkin seeds, chia seeds, and sesame seeds are excellent sources.
Nuts: Almonds, cashews, and Brazil nuts offer a high magnesium content.
Legumes: Include black beans, lentils, and chickpeas in your meals.
Green Leafy Vegetables: Spinach, kale, and chard are nutrient-dense options.
Whole Grains: Brown rice, quinoa, and whole-wheat products retain more magnesium than refined grains.
Other Sources: Dark chocolate and avocados are also good sources.

Considerations for Supplementation

For athletes with consistently high training loads, dietary intake alone may not be sufficient, and supplementation may be warranted. It is important to choose a highly bioavailable form of magnesium and to consult with a sports dietitian or healthcare professional before starting supplementation. Supplementing regularly, rather than just on race day, is more effective for building and maintaining magnesium stores.

Comparing Different Magnesium Supplement Forms


Supplement Form	Bioavailability & Absorption	Best For	Potential Side Effects
Magnesium Citrate	High; well-absorbed.	General supplementation; correcting deficiency quickly.	Can have a laxative effect, especially in high doses.
Magnesium Glycinate	High; gentle on the stomach.	Sleep and relaxation; individuals sensitive to GI side effects.	Less potent laxative effect; generally well-tolerated.
Magnesium Oxide	Lower; contains high elemental magnesium but poorly absorbed.	Often used in laxatives; not ideal for correcting deficiency.	Potential for significant GI distress and diarrhea.
Magnesium Malate	High; binds to malic acid.	Energy production; fatigue reduction.	Minimal GI side effects; good for general use.
Magnesium Chloride	Good; can be used topically.	Topical application for muscle soreness; bath soaks.	May cause skin irritation in some individuals.

Conclusion: Prioritizing Magnesium for Peak Performance

It is clear that athletes are at a heightened risk for magnesium depletion due to increased metabolic demands and higher losses through sweat and urine. This depletion can have far-reaching effects, compromising energy levels, muscle function, recovery, and overall performance. By prioritizing a magnesium-rich diet and considering targeted supplementation with highly bioavailable forms when necessary, athletes can effectively manage their mineral balance. Regular, consistent intake is far more beneficial than isolated dosing, allowing the body to build and maintain the stores needed to support strenuous training. By paying attention to this often-overlooked mineral, athletes can ensure they are laying a solid nutritional foundation for achieving peak health and performance. More research on the effects of magnesium supplementation on athletic performance and injury prevention is ongoing.

Frequently Asked Questions

Athletes lose more magnesium primarily due to increased sweating during intense and prolonged exercise. Additionally, studies indicate that exercise can lead to higher magnesium excretion via urine, further contributing to overall depletion.

Early signs of low magnesium in athletes often include muscle cramps or spasms, general fatigue, reduced energy levels, and a noticeable increase in recovery time or muscle soreness after training.

Yes, magnesium deficiency is a common cause of muscle cramps in athletes. Magnesium helps to relax muscles, and when levels are insufficient, the muscles may contract uncontrollably, leading to painful cramps and spasms.

For athletes, a highly bioavailable form of magnesium like magnesium glycinate or citrate is often recommended. Glycinate is known for being gentle on the stomach, while citrate is well-absorbed and effective for addressing deficiency.

Timing depends on your goals. Taking magnesium before a workout can support energy levels and performance, while taking it after a workout, especially in the evening, can aid muscle relaxation and improve sleep for better recovery.

Athletes can prevent magnesium depletion by incorporating magnesium-rich foods into their daily diet. Examples include leafy green vegetables, nuts, seeds, whole grains, and legumes.

Yes, magnesium is essential for athletic recovery. It helps reduce inflammation, aids muscle tissue repair, and supports protein synthesis, all of which contribute to faster recovery and reduced muscle soreness.