(2 customer reviews)


Daily antioxidant support for stronger, more resilient muscles.

Available sizes:

  • 2-lb container (32-day supply for 1 horse)
  • 20-lb container (320-day supply for 1 horse)
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Product Description

Why choose Myo-Guard?

Myo-Guard was developed to sustain optimal performance in horses of all types. It provides a blend of antioxidants that support healthy muscle function during training and competition. Horses with healthy muscles have more stamina and strength, are quicker to recovery after vigorous exercise, and are less likely to develop muscle disorders.

Fighting oxidative stress

Antioxidants protect cells and tissues from a normal metabolic process called oxidation, which is the use of oxygen to break down carbohydrates, fats, and protein for energy. A byproduct of oxidation is the formation of free radicals, compounds that damage cells and tissues. This damage is also known as oxidative stress. Horses at rest typically have enough antioxidants to ward off the ill effects of normal oxidative stress, but horses being asked to exercise on a daily basis may need supplementation to meet the increased demand for antioxidants caused by increased muscle activity. In the performance horse, signs of oxidative stress may surface as muscle soreness or stiffness and delayed recovery from intense exercise. Myo-Guard contains a unique blend of antioxidants, including natural vitamin E, selenium, and vitamin C. Supplementing with Myo-Guard helps the horse maintain sufficient antioxidant levels during periods of training and competition.

  • Myo-Guard contains natural vitamin E, selenium, vitamin C, and magnesium


  • The natural vitamin E in Myo-Guard is preferentially transported throughout the body and is retained in tissues for longer periods of time than synthetic vitamin E


  • Myo-Guard helps maintain optimal muscle function, which reduces the incidence of stiffness and soreness after a challenging workout or competition


  • What is oxidation?

  • Oxidation is a normal metabolic process in which fats, carbohydrates, and proteins are converted into energy to fuel body functions. Without oxidation, horses couldn’t work or play. An unavoidable side effect of oxidation, however, is the production of free radicals: molecules capable of destroying cellular structure and tissues.

  • How does exercise affect oxidation rates?

  • As the body uses more and more oxygen to drive athletic effort, free radical production increases. This hyperproduction of free radicals may provoke significant tissue damage.

  • How do free radicals harm cells?

  • Free radicals, or reactive oxygen species (ROS), are unstable atoms with unpaired numbers of electrons that are formed when oxygen interacts with other molecules in all cells. Once formed, these reactive radicals can initiate chain reactions resulting in a cascading negative effect on many other molecules within cells and cell walls, which in turn causes oxidative stress within the animal. Free radicals are commonly produced as part of normal cell metabolism, but also can become excessive following intense exercise, injury, or disease. Left uncontrolled, free radicals can cause considerable irreparable damage to cells and cell membranes. They can alter the structure of cell membranes, and create havoc to polyunsaturated fatty acids (PUFA), proteins, and DNA within cells. The more active the cell, the greater the potential risk of cellular damage. Excessive free radical production or oxidative stress results when the formation of free radicals overwhelms the body’s ability to break the chain reactions that take place and an imbalance between production and removal of free radicals occurs.

  • What is an antioxidant?

  • Antioxidants are dietary compounds that inactivate free radicals and block oxidative reactions. Free radicals produced as a result of infrequent, low-intensity exercise can usually be neutralized by natural antioxidant defense systems. However, excessive production of free radicals, which often occurs with intense exercise, may overwhelm normal antioxidant mechanisms and ultimately damage cells and tissue. Supplementation with a powerful medley of antioxidants may be necessary for horses training for or competing in demanding sports.

  • Which antioxidants do horses require?

  • Vitamin E, selenium, and vitamin C are present in the bodies of horses. Vitamin E is the most widely known and effective antioxidant. Natural vitamin E is a highly potent form of vitamin E that protects the stability of the cellular membranes and provides a defense against oxidative stress. Unlike synthetic vitamin E, natural vitamin E is preferentially absorbed and transported throughout the body. It is also retained in tissues for longer periods of time.

    Selenium acts in concert with vitamin E to prevent oxidative insult to cells and tissues. Vitamin C, on the other hand, safeguards structures within the cell. In addition, vitamin C has been found to aid in the regeneration of vitamin E in the body. Once vitamin E inactivates free radicals, it is usually no longer useful to the body. In the presence of vitamin C, however, the antioxidant properties of vitamin E can be restored. A balanced mix of antioxidants provides comprehensive cellular protection, which leads to healthier muscles that recover more quickly from exhaustive exercise.

  • What are some visible signs that my horse needs additional antioxidants?

    • Reduced tolerance for work due to fatigued muscles
    • Muscle soreness and delayed recovery from work
    • Episodes of sporadic or chronic tying-up (exertional rhabdomyolysis)
  • Which equine athletes may benefit from antioxidant supplementation?

  • Increased oxidative stress has been measured in horses performing high-intensity, short-duration exercise and low-intensity, long-duration exercise. Therefore, additional antioxidants would be appropriate for any horse that participates in regular, demanding exercise, regardless of discipline.

  • Can antioxidants benefit my horse after a stressful performance or if muscle damage has already occurred?

  • Yes. It is recommended that antioxidants be administered following hard work when signs of muscle fatigue and damage are evident. Antioxidants will help horses recover from work sooner and return to feed more quickly, eliminating downtime between performances and training periods.

  • Don’t most horse feeds contain selenium and vitamin E? Why would my horse need more?

  • Forages and most fortified concentrates contain vitamin E and selenium in amounts that meet the nutrient requirements for mature horses at maintenance. The amount of these two nutrients found in the average daily horse ration is not, however, enough to meet the demands of horses undergoing strenuous training and competition, and will not provide enough to help horses recover from hard work, especially if they have gone off feed.

  • Do I need to feed Myo-Guard every day?

  • Yes. Myo-Guard should be fed daily when horses are in training or competing. Nutritionists have found that most performance horses require supplementation to meet the additional antioxidant usage resulting from consistent, demanding muscle activity. Providing antioxidants on a routine basis will help maintain adequate antioxidant levels in the body’s tissues so horses have access to them they need them.

Recommended For

Fed daily, Myo-Guard supports healthy muscles during training and competition.

In the last decade, exercise physiology and nutritional research have shown that most performance horses require supplemental antioxidants above and beyond what is provided by their daily diet of hay and concentrates. Additional antioxidant requirements are the result of consistent, demanding muscle activity. Providing antioxidants on a daily basis will help maintain adequate antioxidant levels in the body’s tissues so horses have access to them they need them.

Myo-Guard was designed to be fed daily to support adequate antioxidant levels in hard-working horses of all ages.

Myo-Guard is recommended for:

  • Horses in a regular training or competition program, including:
  • Barrel racers
  • Endurance horses
  • Eventing horses
  • Horses on the show circuit
  • Hunters/jumpers
  • Polo ponies
  • Racehorses
  • Reiners
  • Western pleasure horses during a long show season
  • Working cow horses
  • Young horses in training
  • Horses that are used heavily (e.g., school horses, trail riding mounts, carriage horses)
  • Horses that experience exercise-induced muscle stiffness, soreness, or tying-up


Formulated to support optimal performance.

Myo-Guard is a blend of ingredients chosen because of their ability to support healthy muscle activity. When muscles function properly, horses are able to perform to their highest potential.

Natural Vitamin E

Vitamin E is unique among vitamins in that it is not required for a specific metabolic function. As alpha-tocopherol, vitamin E’s major function appears to be the body’s most important fat-soluble antioxidant. A powerful antioxidant, vitamin E supports healthy cell membranes by reducing free radical-induced damage. Thus, vitamin E is notably essential for the proper function of the reproductive, muscular, nervous, circulatory, and immune systems. Natural is best! Unlike synthetic vitamin E, natural vitamin E is preferentially absorbed and transported throughout the body. It is also retained in tissues for longer periods of time, making it readily available when horses need it most. Myo-Guard contains 1000 IU of natural vitamin E per ounce.

Vitamin C

This antioxidant supports healthy tissues by scavenging oxygen radicals from aqueous solutions, helping to reduce free radical damage. In addition, vitamin C has been found to aid in the regeneration of vitamin E in the body. Once vitamin E inactivates free radicals, it is usually no longer useful to the body. In the presence of vitamin C, however, the antioxidant properties of vitamin E can be restored. Myo-Guard provides 1500 mg of vitamin C (as ascorbic acid) per ounce.


Selenium is required for the production of glutathione peroxidase, an enzyme that neutralizes peroxides so they can no longer damage muscle cell integrity by reacting with the cells’ lipid membrane. Selenium works in concert with vitamin E to support a reduction in oxidative stress. One ounce of Myo-Guard provides 1 mg of selenium.


Magnesium is a mineral that supports proper muscle and nerve function. During exercise, magnesium, as well as other electrolytes, is lost in sweat. Much of the body’s magnesium is stored in the skeleton. The transfer from bone to bloodstream is not efficient enough for rapid replacement of magnesium losses through heavy sweating. Therefore, supplementing an equine athlete’s ration with magnesium may be necessary for optimal muscle function. Myo-Guard supplies 3000 mg of magnesium per ounce.

Serving and Storage

Myo-Guard serving instructions:

1 scoop = 1 oz

1 scoop provides 1,000 IU natural vitamin E; 1,500 mg vitamin C; 1 mg selenium

Mix 1 scoop per day in feed ration.

Do not serve more than the recommended amount.

Storage and shelf life:

Store Myo-Guard in a cool, dry place and keep lid tightly closed between uses. Shelf life is 24 months from date of manufacture when stored under suitable conditions.

More Information

For more information on antioxidants and Myo-Guard visit our blog and explore these titles.

Vitamin E and the Performance Horse – A Winning Combination

Researchers Confirm Vitamin E Lower in Horses Without Access to Pasture

Vitamin E:  An Essential Nutrient for Horses

Think “E” for Excellent Nutrition

The Vitamin E Controversy

Selenium: an essential mineral

Vitamin E and Equine Motor Neuron Disease

Selenium: how much is in your horse’s diet?

Does your horse need extra vitamins? Maybe…

Vitamin E Necessary for Optimal Health

Influence of Source and Quantity of Supplemental Vitamin E on Equine Serum and Cerebrospinal Fluid a-Tocopherol and Its Implication for Neurologic Diseases

Myo-Guard™: What’s inside the bucket?

2 reviews for Myo-Guard™

  1. Holly Jones (verified owner)

    I do NATRC which is endurance with horsemanship obstacles on the trail. You receive two scores, one for horsemanship and one for the horse. The horse is judged on pulse and respiration, and soundness among other things. We were doing OK, but during the last vet check we would have points taken off for grade 1 lameness and attitude (she was tired). The grade 1 lameness is when the judge can see the horse is stiff and tight or could be slightly off on one leg. Grade 1 is not bad, just that the horse is just a little off.

    A friend suggested I try Myo-Guard. I feed the product once a day with my mare’s grain. This product is great because I can feed it during competitions.

    This is the difference I have seen since starting Myo-Guard. We are having 9 heart beats per minute and 4 breaths at the vet check during the competition. She is checking out SOUND with a great attitude. No muscle soreness. In my competition in October we won our division and we won sweepstakes. Sweepstakes is the highest scoring horse. My mare scored a 98 out of 100! My November ride we won 1st place in horse and 2nd place in horsemanship. We tied for sweepstakes and with the tiebreaker we did not win. I have seen a difference in her performance.

    Holly Jones, owner of Rock Creeks Wild Pepper (Mustang)
    Waco, Texas

  2. Brittany Schruefer (verified owner)

    My horse experienced some muscle atrophy due to a host of veterinary issues, primarily due to his vitamin E and selenium levels being on the low end of normal. After just one month on Myo-Guard, he is building muscle faster and coming out less stiff than ever before!

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