Despite carnitine being one of the most popular supplements, it's essential to know what some of the potential benefits are.
In addition to being essential for fat metabolism, carnitine appears to benefit athletic performance in several different ways ranging from improving endurance to sparing energy reserves (1, 2).
In this brief article, we’ll go over some of the main benefits of having carnitine in your routine.
What Is Carnitine?
L-Carnitine is an amino acid that is often consumed through the diet. Not far different from our own bodies, carnitine is found in animal proteins and is typically ingested through meat consumption (3).
In the body, carnitine plays an essential role in shuttling fatty acids into structures known as mitochondria, which transform fats into usable energy (3).
Because of its potential role in fat metabolism, it’s been a subject of interest, particularly for athletic performance.
Main Benefits Of Carnitine
Even though carnitine plays an essential role in fatty acid metabolism, it appears that it provides a number of different benefits, particularly for the athlete.
Improved Endurance Ability
In particular, it appears that regularly using carnitine can help increase time to exhaustion, even at higher intensities (1).
In one interesting study, trained rugby players were given a placebo, a carnitine-only supplement, or a supplement containing carnitine and caffeine. One hour after ingesting their supplement, participants took part in a fairly intense cycling endurance test.
During this test, the rugby players cycled for 45 minutes at 60% of their V02 Max. At the 45-minute mark, however, the intensity was increased to 80% and remained at that intensity until the athlete could no longer maintain 50 rpm.
The amount of time that each participant spent cycling at 80% of their V02 Max was considered their time to exhaustion.
Impressively, the researchers showed that when subjects used carnitine an hour before cycling, they significantly extended their time to exhaustion. In fact, compared to placebo, those using carnitine increased their cycling time by approximately ten minutes (1).
For an endurance athlete, significantly increasing time to exhaustion means that you can perform at a higher intensity for a more extended period, which is, of course, every endurance athlete's goal.
Reduced Muscle Damage
As an athlete, muscle damage is an issue that can limit your growth and reduce your performance. Fortunately, some research suggests that carnitine might limit this damage (4, 5).
Muscle damage is often a result of overusing certain muscle groups and, in particular, a result of overloading your muscles through the eccentric, or, stretching portion of an exercise (6).
Your muscles have structures called sarcomeres. These structures contain components that are responsible for generating force and contracting your muscles.
However, when your muscles are overstretched or overloaded through using resistance or high forces (like landing after a jump) repeatedly, the edges of these sarcomeres can tear, resulting in damage and soreness (7).
For performance, this damage limits factors like force output and the ability to generate power, which is no good for the athlete (8).
However, carnitine appears to limit the effect of damaging exercise.
For example, one study enrolled participants and provided them with carnitine or placebo daily for three weeks. Then, each subject performed five high-rep squat sets with only two minutes of rest in between (5).
Afterward, for the following four days, the subjects underwent MRI scans to observe the amount of muscle damage incurred and their recovery.
Based on the findings, when the subjects used carnitine, they displayed approximately 43% less damage on average compared to participants consuming a placebo (5).
But, there were even more benefits.
Secondary to muscle damage, the researchers also measured each participant’s perceived soreness for the following four days as well. They found in addition to reduced damage, carnitine users were significantly less sore at all time points compared to placebo (5).
Best of all, these findings have been duplicated multiple times.
In similar study formats, researchers consistently show that carnitine use limits markers of muscle damage and soreness perception (4, 5, 9).
But Isn’t Muscle Damage Good For Muscle Growth?
Muscle damage has long been thought necessary for building muscle. The idea is simple: you tear your muscles, and they rebuild stronger!
Unfortunately, muscle growth is a bit more complicated.
New research is beginning to show that muscle growth, or the increase in size and strength of your muscles, occurs after muscle damage is repaired instead of as a direct result of it (10).
Our bodies grow according to protein balance (11).
Each day some proteins degrade, and some grow. When growth exceeds breakdown, your muscles get bigger. In this case, you have a “net positive protein balance.”
When you damage your muscle, the amount of breakdown overcomes the amount of protein growth creating a “net negative protein balance.”
To get back to baseline, where no protein is being grown or degraded, that damage has to be repaired. Muscle damage makes building a net positive balance, and thus, muscle growth more difficult.The benefit of carnitine here is that it appears to limit how much damage or breakdown is occurring. Essentially, you’ll get the stimulus from the workout but limit the damage that’s happening, potentially making your progression a bit easier (5).
Carnitine Spares Energy Reserves During Exercise
One of the more exciting benefits of consistent carnitine supplementation is that it appears to help spare energy, like glycogen, during lower-intensity activities (2).
In this study, endurance-trained athletes were given either carbohydrates or carbohydrates and carnitine daily for 24 weeks. At the end of the study, the athletes performed a 60-minute cycle test where they performed at 50% of their V02 Max during the first half and 80% for the remaining 30 minutes.
After analyzing muscle biopsies, the researchers reported that when these athletes used carnitine, they significantly spared muscle glycogen during the initial half of the test compared to the group only consuming carbs (2).
For an endurance athlete, this is crucial.
Sparing glycogen during lower-intensity activities means that more is available for higher intensity bursts. By saving glycogen when it's not needed, you'll be able to perform at a higher intensity for a more extended amount of time.
And that’s what they showed in this study. Athletes who used carnitine daily showed higher work output during the performance test compared to those only consuming carbs (2).
Carnitine & Glyco-Muscle Fueler: A Good Combination
Like with creatine, your muscles need to be saturated with carnitine to show results. However, some studies suggest that consuming carnitine alone is difficult for the body to use (12, 13 2).
Fortunately, research also suggests that elevated insulin, or the hormone that helps push sugar out of the blood and into muscle, can help drive carnitine into the muscle as well (2, 14).
Fortunately, Glyco-Muscle Fueler incorporates a particular carbohydrate known as Karbolyn. Because it's a carb source, it effectively elevates insulin, which can help improve the saturation of carnitine in your muscles!
Overall, research suggests that carnitine is a smart choice if you’re an athlete.
Studies suggest that regular carnitine use can improve performance, spare energy reserves, and even limit the damaging effects of exercise, which can help you train harder and grow more efficiently (1, 4, 5, 9).
If these benefits sound attractive to you, using a supplement like Glyco-Muscle Fueler is a no-brainer.
- Cha, Y. S., Choi, S. K., Suh, H., Lee, S. N., Cho, D., & Lim, K. (2001). Effects of carnitine coingested caffeine on carnitine metabolism and endurance capacity in athletes. Journal of nutritional science and vitaminology, 47(6), 378-384.
- Wall, B. T., Stephens, F. B., Constantin‐Teodosiu, D., Marimuthu, K., Macdonald, I. A., & Greenhaff, P. L. (2011). Chronic oral ingestion of l‐carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. The Journal of physiology, 589(4), 963-973.
- Kraemer, W. J., Volek, J. S., & Dunn-Lewis, C. (2008). L-carnitine supplementation: influence upon physiological function. Current sports medicine reports, 7(4), 218-223.
- Spiering, B. A., Kraemer, W. J., Vingren, J. L., & Hatfield, D. L. (2007). Responses of criterion variables to different supplemental doses of L-carnitine L-tartrate. Journal of Strength and Conditioning Research, 21(1), 259.
- Volek, J. S., Kraemer, W. J., Rubin, M. R., Gómez, A. L., Ratamess, N. A., & Gaynor, P. (2002). L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress. American Journal of Physiology-Endocrinology and Metabolism, 282(2), E474-E482.
- Proske, U., & Morgan, D. L. (2001). Muscle damage from eccentric exercise: mechanism, mechanical signs, adaptation and clinical applications. The Journal of physiology, 537(2), 333-345.
- Morgan, D. L., & Proske, U. (2004). Popping sarcomere hypothesis explains stretch‐induced muscle damage. Clinical and Experimental Pharmacology and Physiology, 31(8), 541-545.
- Doma, K., Leicht, A., Sinclair, W., Schumann, M., Damas, F., Burt, D., & Woods, C. (2018). Impact of exercise-induced muscle damage on performance test outcomes in elite female basketball players. The Journal of Strength & Conditioning Research, 32(6), 1731-1738.
- Ho, J. Y., Kraemer, W. J., Volek, J. S., Fragala, M. S., Thomas, G. A., Dunn-Lewis, C., ... & Maresh, C. M. (2010). l-Carnitine l-tartrate supplementation favorably affects biochemical markers of recovery from physical exertion in middle-aged men and women. Metabolism, 59(8), 1190-1199.
- Damas, F., Libardi, C. A., & Ugrinowitsch, C. (2018). The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis. European journal of applied physiology, 118(3), 485-500.
- Smiles, W. J., Hawley, J. A., & Camera, D. M. (2016). Effects of skeletal muscle energy availability on protein turnover responses to exercise. Journal of Experimental Biology, 219(2), 214-225.
- Brass, E. P. (2000). Supplemental carnitine and exercise. The American journal of clinical nutrition, 72(2), 618S-623S.
- Brass, E. P., Hoppel, C. L., & Hiatt, W. R. (1994). Effect of intravenous L‐carnitine on carnitine homeostasis and fuel metabolism during exercise in humans. Clinical Pharmacology & Therapeutics, 55(6), 681-692.
- Stephens, F. B., Constantin-Teodosiu, D., Laithwaite, D., Simpson, E. J., & Greenhaff, P. L. (2006). Insulin stimulates L-carnitine accumulation in human skeletal muscle. The FASEB journal, 20(2), 377-379.