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L-carnitine: what is it and how does it work in our body?

L-carnitine: what is it and how does it work in our body?

October 4, 2022

Nutritional supplements with L-carnitine have become popular in recent years to improve athletic performance and to promote weight loss, in addition to other medical uses.

But what is L-carnitine exactly? How does it work in our body? And, most importantly, is it truly effective in all your applications? In this article we will answer these questions.

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What is L-carnitine?

L-carnitine is an amino acid produced by the kidneys and the liver and that is stored in the brain, heart, muscles and sperm. It is involved in the transformation of fats into energy and is attributed antioxidant properties.


It is one of the two isomers or molecular structures of carnitine. While L-carnitine has positive effects on the body, the other isomer, D-carnitine, inhibits the activity of L-carnitine.

L-carnitine It is found mainly in red meat , especially in lamb and veal. It can be found in moderate amounts in pork, cod, chicken breast and dairy products, and there is also a small concentration of this amino acid in some vegetables and cereals.

This compound is used as a supplement to treat various disorders of the body and to enhance metabolic activity . However, not all of its applications have been endorsed by scientific research.


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How does it work in the body?

L-carnitine serves to transport fatty acids through the mitochondrial membranes of cells. The enzyme carnitine palmitoyltransferase binds L-carnitine molecules to fatty acids.

This amino acid has antioxidant effects : it eliminates free radicals, particles that if accumulated in excess alter the DNA and damage the cells by oxidation, being able to favor the appearance of cancer.

L-carnitine deficits can occur in the organism due to genetic alterations or malnutrition, as well as the exclusive consumption of plant foods.

The lack of L-carnitine can cause different alterations according to age, severity and the organs involved. Some of the most characteristic symptoms of this disorder are the reduction in glucose levels (hypoglycemia), the appearance of heart muscle diseases (cardiomyopathy) and fatigue.


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What is it for?

The uses given to L-carnitine as a nutritional supplement are multiple, although not all of its supposed benefits have been demonstrated. In this section we will detail the scientific evidence about the different applications of this substance.

In no case is it recommended to take L-carnitine supplements without medical prescription as it is a drug in experimental phase in most of its applications.

1. Diseases of the kidneys

The kidneys participate in the production of L-carnitine, so that the blood levels of this amino acid are affected when there is a kidney disease . It is in this field that external L-carnitine is more clearly effective.

The efficacy of L-carnitine supplements has been demonstrated as an adjuvant for people undergoing hemodialysis, a form of therapy that replaces the function of the kidneys when they do not act properly. This not only reduces the symptoms of L-carnitine deficiency but can also prevent them.

2. Cardiovascular disorders

Scientific studies have found preliminary evidence in favor of the use of L-carnitine in diseases of the heart and the circulatory system in general.

Specifically, L-carnitine can increase the capacity of physical effort of people diagnosed with angina or heart failure, as well as reducing the risk of mortality after heart attacks and in cases of heart inflammation (myocarditis).

On the other hand, it has been suggested that L-carnitine reduces pain and improves mobility in people with atherosclerosis, and that it prevents the onset of this disorder by reducing cholesterol and triglyceride levels.

3. Weight loss

There is not enough scientific evidence to affirm that L-carnitine is effective as a supplement to reduce weight, although this is one of its most famous applications.

Some studies claim that this compound reduces the accumulation of fat and increases muscle mass. In addition, the effects of L-carnitine to reduce fatigue would facilitate weight loss indirectly.

4. Male infertility

Male infertility has been linked with low levels of L-carnitine. According to research, it is likely that supplements of this amino acid increase the amount and mobility of sperm.

5. Diabetes

L-carnitine can help regulate blood glucose levels of people with diabetes if taken as a supplement to the specific medication to treat this disease.

In the same sense, it may be effective to reduce the symptoms of diabetic neuropathy, which occurs when high glucose levels damage the nerves of the extremities, causing pain and numbness.

6. Hyperthyroidism

L-carnitine seems to reduce the symptoms of hyperthyroidism , a disorder characterized by excessive secretion of thyroid hormones. Studies in this regard are promising but at the moment inconclusive.

The typical symptoms of hyperthyroidism include tachycardia, anxiety, insomnia, physical weakness and tremors.

7. Erectile dysfunction

Although more studies are needed to confirm this, it has been suggested that L-carnitine Can increase the effectiveness of Viagra in cases of impotence, especially in men who do not respond adequately to this medicine and who have undergone prostate surgery.

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8. Fatigue

There is preliminary scientific evidence about the usefulness of L-carnitine for reduce fatigue related to age , cancer, celiac disease, hepatitis, multiple sclerosis and chronic fatigue syndrome, as well as fatigue in general.

9. Sports performance

Intense physical activity has been linked to a decrease in L-carnitine levels, which is why Many athletes use these supplements to improve their performance . However, although some studies support this hypothesis, it can not be said that L-carnitine is useful for improving sports performance.


Nutrition & Dietitian Careers : What Is L-Carnitine? (October 2022).


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