by Casie Bazay

Review of antioxidants for horses: L-Carnitine

Review of antioxidants for horses: L-Carnitine

Published: January 2021 | Updated: June 2024

L-carnitine likely isn’t something horse owners have spent much time considering. Sure, many of us have probably seen it on a list of supplement ingredients somewhere, but what is L-carnitine exactly? And how does it benefit our horses? 

Let’s begin with the former question: If you aren’t familiar with it, carnitine is an antioxidant derived from an amino acid, or the building blocks of protein. It is found in nearly every cell of an animal’s body and exists as several different compounds including acetyl-L-, propionyl-L- and L-carnitine. However, in horse antioxidant supplements, you will usually find it as acetyl-L- or L-carnitine. 

Carnitine compounds play an important role in energy production by transporting long-chain fatty acids into the cell’s mitochondria (the powerhouse of the cell) so they can then be used as fuel. Essentially, carnitine helps the body turn fat into energy through a process called beta-oxidation. 

Carnitine is synthesized almost exclusively in the liver by the amino acids lysine and methionine, and it prevents the accumulation of toxic compounds by transporting them out of the cells. High carnitine levels are found in both skeletal and cardiac muscles since both use fatty acids as dietary fuel. 

However, the skeletal muscles are the primary reservoir of carnitine in the body, with a concentration at least 200 times higher than blood plasma.

Though the average horse naturally produces a sufficient amount of carnitine on their own, performance horses in hard work may require more carnitine than their body can produce. Additionally, genetic conditions such as Polysaccharide Storage Myopathy (PSSM) may affect production of carnitine, necessitating supplementation. 

The Effects of Strenuous Exercise

As noted above, one of the most common reasons why horses may need carnitine supplementation is due to routine strenuous exercise, which can cause tissue damage and lead to an extended recovery period. 

Muscle damage is characterized by an increase in blood creatine kinase and therefore can be measured through blood work. 

Researchers have also learned that musculoskeletal fatigue can reduce contractile activity and energy reserves in the muscles, which may also lead to stiffness within tendons and ligaments. With that said, a variety of factors can affect time to fatigue and recovery time, including the horse’s age, sex, fitness level, as well as the intensity of the exercise the horse is exposed to. 

Horses in good fitness will have a higher number and size of muscle mitochondria, which allows for improved aerobic capacity, less reliance on glycogen, and greater fatigue resistance. However, even horses that are well acclimated to intense exercise will experience muscle fatigue and may be in need of dietary strategies to help accelerate the process of muscle repair and recovery. 

Ideally, these strategies should allow them to return to work more quickly and also reduce the likelihood of tendon and joint damage. Fortunately, studies show that carnitine supplementation can be beneficial in this instance.

The Benefits of L-Carnitine for Horses

As mentioned above, skeletal muscle is the largest reservoir of carnitine in the body; therefore, intense exercise will have an effect on the amount of carnitine available to the horse.

Hard-working horses can benefit from L-carnitine supplementation since exercise greatly increases the demand on muscles to produce energy from glucose, glycogen (stored glucose), and fats. A high quality L-carnitine supplement can help horses better adapt to training, reduce muscle soreness, and shorten recovery time. 

According to Dr. Keith Latson, equine surgeon and FullBucket co-founder, “L-Carnitine in horse supplements provides an important nutritional link in exercise recovery due to its role in fatty acid oxidation and energy metabolism. Often we think about nutritionally supporting equine athletes with the right energy to perform. Feeding and supplementing our animals with critical nutrients like L-carnitine promotes overall performance and muscle health, while optimizing recovery from oxidative stress, in both the short- and long-term.”

Long-term supplementation of carnitine (7+ days) is thought to increase muscle carnitine content, which then leads to improved fatty acid oxidation efficiency and possibly, improved performance. 

It is important to keep in mind that carnitine supplementation is not a substitute for adequate rest periods between exercise. 

These rest periods are needed to ensure that macrophages and monocytes are available for tissue repair. In fact, horses with inadequate rest periods between bouts of intense exercise may take even longer to recover; they can also be at higher risk of developing infection or immune system damage.

L-Carnitine for Managing PSSM

Since PSSM horses have a genetic mutation which leads to abnormal glycogen levels in the muscle cells, they need a stable supply of glucose in order to keep their cells functioning correctly. L-carnitine addresses this problem by encouraging the burning of fats as fuel and also leading glucose to be burned by the mitochondria (instead of being stored as glycogen). 

In fact, supplementing with as little as 10 grams of L-carnitine per day for a 1,000 lb. horse has been found to improve symptoms of PSSM. 

Because L-carnitine is so important in muscle health and recovery, it’s one of the top ingredients in FullBucket’s Medical Muscle supplement. This product is specifically designed for hard-working performance horses as well as those with muscle disorders such as PSSM or recurrent rhabdomyolysis. 

Medical Muscle combines L-carnitine with the powerful antioxidant, astaxanthin, since studies have shown that these two ingredients can lead to a reduction of tying up in exercising horses. This product is essentially a super antioxidant which is 6000 times stronger than vitamin C. It supports muscle, tendon, and joint health, energy and endurance, and exercise recovery. 

With antioxidants such as L-carnitine, it’s important for horse owners to understand when supplementation might be needed. 

The average horse is likely fine without additional L-carnitine in their diet, but many performance horses, as well as those with muscle disorders, like the ones mentioned above, can benefit from this incredible nutrient through select equine antioxidant supplements

The recommended dosage of L-carnitine for horses will vary depending on their specific condition and weight. However, the dosage commonly recommended is 1 gram per 100 lbs of body weight per day. If you aren’t sure how much L-carnitine to give your horse, your veterinarian should be able to give you a recommendation. And if you’re searching for a high-quality L-carnitine supplement with additional benefits, Medical Muscle is the way to go. 

Read More:

  1. Metabolic Functions of L‐Carnitine
  2. A Carnitine-Containing Product Improves Aspects of Post-Exercise Recovery in Adult Horses

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