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Magnesium (Mg) as a supplement for the athlete horse

Updated: Jun 6, 2022



Magnesium is a chemical element with the symbol Mg and atomic number 12.

Magnesium is by far the most essential mineral the horse need for proper nerve and muscle function.

Magnesium functions as an electrolyte, it plays a huge roll in protein synthesis and is definitely by far the most important mineral regulating over 325 enzymes in the body of the horse.

Working and competing horses do need Magnesium as supplementation

Working and competing horses do need more magnesium intake than not working horses, as magnesium is one of the minerals that are found in the horse's sweat. The more it sweats the higher the loss of Mg and the bigger need for Mg as supplementation.

Magnesium is a macro mineral, meaning it is required in larger amounts compared to other minerals.

According to the National Research Council (NRC), the daily requirement for horses is estimated at 20 mg per kg of body weight.

Calculated for a 500 kg horse, the magnesium intake should be 10 g per day to maintain proper functions.

In the case of horses that are in a medium to heavy exercising routine the required amount becomes 1.5 to 2 times more than the required amount for proper body functions.

For a 500 kg horse, the requirement during training and competition will be 15 to 20 g per day. This will help compensate for the magnesium that is lost in sweat and help muscles recover after exercise.

When the Mg levels are low in the diet and from exercise the horse can become excessively irritable, nervous, or they may chronically tie-up. If your horse experiences thumps (synchronous diaphragmatic flutter) they are most likely low on magnesium.

Colourful horse running with powder minerals
10 Reasons why your horse need healthy Magnesium levels
  1. Proper Muscle Function: Proper muscle function is achieved while working closely with calcium. When the muscles receive nerve signals telling them to contract, calcium is released from special compartments within cells and moves onto muscle fibres causing them to contract. Magnesium stops the contraction by pushing calcium back into these compartments. A very complexed function but extremely essential for proper muscle functionality.

  2. Muscle Relaxation: By enabling muscle relaxation, it supports the fast recovery of muscles and help to ease muscle pain and cramping in horses in heavy exercise routines.

  3. Enhanced Oxygen: Magnesium can have a performance boosting effect for equine athletes, supporting enhanced oxygen delivery to muscles, muscle strength, and metabolic processes that result in protein synthesis.

  4. Proper Nerve Function: Magnesium helps nerve cells in the transmitting of signals to each other and to muscles by regulating ion balance across cell membranes.

  5. Calming Functions: It is known to have a calming effect on horses, helping to ease muscle tremors and nervousness. It is frequently fed as a mood supplement to horses showing signs of excitability or abnormal behaviour.

  6. Stress Reliever: Magnesium improves the tolerance to stress factors and resistance to illness and injury. High levels of stress is one of the main causes of magnesium levels to be faster depleted in the body. Ensuring optimal levels of magnesium intake can help to speed up return to homeostasis following exposure to an external stressor.

  7. Fat Distribution: It can contribute to normal fat distribution in horses by minimizing cresty neck or fatty pockets.

  8. Insulin Sensitivity: Magnesium helps cells respond to insulin. Supplementation with this mineral improves insulin sensitivity, particularly in overweight horses.

  9. Laminitis Prevention: It helps in the prevention of laminitis in horses, especially in those that are more prone to laminitis in the spring. Horses with laminitis are often found to have low levels of Magnesium in their bloodwork.

  10. Healthy Bones: Optimal levels of magnesium help with absorption of calcium from the diet. This can support healthy bones and overall well-being in your horse.


Marnite® is a unique multi-mineral complex, providing bioactive MAGNESIUM and CALCIUM in perfect ratio of 1:2 along with 20 other elements. Unlike other mineral sources used in supplement preparation, Marnite® is a 100% natural mineral product (with natural slow release magnesium) that is neutral and is easily absorbed by the horse’s digestive system.

Marnite® is a 100% natural product with no chemical intervention.

Marnite® is a proven bioavailable, 100% absorbable active ingredient, supported by validated test protocols and test results in compliance with international protocols, guidelines and standards.

Marnite®’s main elements consist of, Magnesium (Natural Slow Release Magnesium) and Calcium in perfect ratio 1:2, with 20 other elements.

Signs of Magnesium deficiency in horses
  • Nervousness/Excitability/Anxiety

  • Unable to relax or focus

  • Muscle tremors, spasm, twitching, flinching skin, trembling

  • Muscle pain or cramps

  • Not tolerant of long periods of work

  • Highly sensitive to sound or movement

  • Hypersensitive skin

  • Irritable moods

  • Resistance to training

  • Fatigue

  • Irregular heartbeat

  • Teeth grinding

  • Increased perspiration and anhidrosis

In more serious cases, the following rare symptoms may be observed:

  • Chronic Exertional Rhabdomylosis (tying up), especially tight, sore backs

  • Irregular heartbeat

  • Increased respiratory rate or laboured breathing

  • Metabolic dysfunction, abnormal fat distribution and weight gain

  • Muscle convulsions

Avoid Magnesium deficiency - Supplement with EquesPro powered by Marnite®

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