What Is L-Carnitine?
Carnitine is a type of amino acid that benefits energy levels by transporting fatty acids into the mitochondria where they can be burned up and used as fuel. For this reason, many take carnitine as a weight loss supplement to help bump up fat burning.
Carnitine occurs in two forms, or isomers: L-carnitine and D-carnitine. L-carnitine is the active form that plays a role in energy metabolism and production. It is produced within the body, but it can also be taken as a supplement or found in many different protein foods as well. In supplement form, it’s available as a capsule, liquid or even injectable.
A deficiency in carnitine can be caused by an inadequate intake, excess loss through diarrhea or dialysis, liver disorders, the use of certain medications, and some genetic disorders. Additionally, because it is primarily found in animal products, vegans and vegetarians are at a higher risk of deficiency.
Although many people take L-carnitine as a way to speed up weight loss and fat burning, carnitine benefits include enhancing brain function, preventing muscle damage, regulating blood sugar and increasing endurance as well.
- Increases Endurance
- Enhances Weight Loss
- Prevents Muscle Damage
- Amps Up Fat Burning
- Boosts Brain Function
- Regulates Blood Sugar
1. Increases Endurance
Because L-carnitine plays a central role in energy production, many athletes begin taking it as a way to enhance endurance and boost athletic performance. Both human and animal studies have confirmed the beneficial effects of this amino acid on endurance levels.
In one study out of Turkey published in the Journal of Strength and Conditioning Research, giving professional soccer players three to four grams of L-carnitine before exercise was found to prolong the time it took to reach exhaustion. (1) Similarly, an animal study out of India published in the journal Wilderness & Environmental Medicine showed that giving rats L-carnitine improved exercise endurance. (2)
For this reason, supplementing with this amino acid may especially benefit endurance athletes, such as long-distance runners, swimmers or cyclists.
2. Enhances Weight Loss
Many people look to L-carnitine as a way to help shed unwanted pounds and lose weight fast. When combined with diet and exercise, some studies have found that supplementing with it can, in fact, be an effective way to enhance weight loss.
One analysis of research out of Iran looked at the results of nine studies and found that supplementing with carnitine led to a significantly greater amount of weight loss as well as a larger drop in body mass index compared to a control group. (3)
However, L-carnitine weight loss results may vary, and other studies have turned up mixed results. In a study out of Australia published in the International Journal of Sports Nutrition and Exercise Metabolism, for instance, 36 obese women took either L-carnitine or a placebo and completed eight weeks of aerobic training. At the end of the study, researchers concluded that L-carnitine had no impact on either total body mass or fat mass. (4)
While L-carnitine may work for some people, it shouldn’t be considered a quick fix. Pair it with regular exercise and a healthy diet to see maximum results.
3. Prevents Muscle Damage
Besides increasing endurance and amping up weight loss, this amino acid also makes a useful supplement for athletes looking to prevent and protect against muscle damage.
In one 2014 study published in the Asian Journal of Sports Medicine, 21 male athletes were given either L-carnitine or a placebo daily for two weeks prior to an athletic test. Compared to the control group, those who took L-carnitine were found to have lower levels of certain markers that indicate muscle damage. (5)
Other ways to aid in muscle recovery include eating lots of anti-inflammatory foods, loading up on fruits and vegetables, and getting enough protein in your diet.
4. Amps Up Fat Burning
Besides increasing weight loss, this amino acid also helps kick up fat burning as well. In one study conducted in Germany, overweight participants received a regular diet, either with or without the addition of L-carnitine. After 10 days, L-carnitine was found to significantly increase the breakdown of fat. (6)
Another study published in the Journal of Physiology showed that increasing the amount of carnitine in the muscles helped prevent fat gain by increasing fat burning and energy expenditure during physical activity. (7)
Other fat-burning foods include apple cider vinegar, bone broth, cayenne pepper and chia seeds.
5. Boosts Brain Function
L-carnitine isn’t just good for your body, but it’s good for your mind as well. In fact, promising research has found that it may positively impact brain function and cognition.
One study conducted by the University of Catania in Italy and published in the American Journal of Clinical Nutrition looked at the effects of daily L-carnitine supplementation on mental and physical fatigue in elderly participants over 100 years old. Not only was it found to reduce total fat mass and increase muscle mass, but it also helped decrease fatigue and improve cognitive function. (8)
Avocados, beets, blueberries and broccoli are also brain foods that can help enhance your focus and memory.
6. Regulates Blood Sugar
Some promising research has shown that carnitine supplementation could aid in maintaining normal blood sugar levels and fighting insulin resistance. Insulin is the hormone responsible for transporting sugar from the bloodstream to the cells where it can be used as fuel. Too much insulin can lead to insulin resistance, decreasing its effectiveness and resulting in high blood sugar.
A study out of Rome published in the Journal of the American College of Nutrition showed that infusing diabetic participants with L-carnitine improved insulin sensitivity and increased the uptake of sugar from the bloodstream. (11) Another small study in 2010 conducted at Sapienza University’s Department of Clinical Medicine in Rome found that combining L-carnitine with caloric restriction helped reduce insulin resistance and increase sensitivity. (12)
Controlling your carb intake, including more fiber and protein foods in your diet, and using natural stress relievers can also help keep blood sugar in check.
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