Function of L-Carnitine and how to take it

Función de la L-Carnitina y cómo tomarla

Many athletes and people who want to lose weight turn to L-Carnitine to achieve their goal. They take it as if it were the holy grail, the philosopher's stone or they think that it will act by magic. The truth is that the function of L-Carnitine is to help you achieve your goals faster, but by itself it will not be enough.

You will need to take care of your diet, have an exercise plan with the appropriate intensity according to your goal, and sleep at least 8 hours in a row. These factors will be decisive in losing a few pounds and maintaining your ideal weight.

In this post we are going to tell you what it is, how it works and the best way to take it to see accelerated results.

What is L-Carnitine?

L-carnitine is a very small molecule, soluble in water, which is highly concentrated in the muscles and a fairly low percentage in the liver and blood.

Also called levocarnitine, it is found as an "L" stereoisomer , which is synthesized in the liver, kidneys, and brain from the essential amino acids: lysine and methionine.

It is important to know that during the synthesis process of L-Carnitine, D-Carnitine is also formed, but only the "L" form is biologically active, so when we talk about carnitine we are referring to L-carnitine.

It was discovered in 1905 by the Russian researchers Gulewitsch & Krimberg, who found it in the musculature of mammals. Hence the trade name derives from the Latin carnis, which means pulp or meat.

These scientists concluded that L-Carnitine was necessary for the biochemical functioning of muscle cells. Its chemical structure was established in 1927 by scientists Tomita and Sendju who discovered the position of the "OH-" group.

In the 1950s, scientists Fraenkel (German) and Benet (American) called it vitamin BT and their research confirmed that L-Carnitine is a key nutritional component for the body, demonstrating that its deficiency leads to a significant decrease in the production of energy and increase the mass of adipose tissue.

What is L-Carnitine?

The body produces it naturally, although it is also integrated into the body by ingesting animal protein and in food supplements. It reaches the tissues through blood circulation and, for its synthesis, it needs the essential amino acids lysine and methionine with the reinforcement of iron and vitamins C, B3 and B6.

What is the function of L-Carnitine and what is it for?

L-carnitine function, being responsible for the metabolism of fats , since it is directly involved in the transport of fatty acids into the mitochondria, the cellular organelles where nutrients are transformed into the energy that you use to function in your day to day and exercise.

It is mainly synthesized in the liver and from there it is transported through the bloodstream to the muscles. It also participates in the metabolism of amino acids, as well as in the production of acetylcholine and stabilizes biological membranes, protecting muscle fibers against their destruction.

All of this is vitally important for anabolic processes, since efficient fatty acid burning provides larger portions of the ATP that stimulates protein synthesis.

Without the activity of L-Carnitine, fatty bodies would tend to accumulate in muscle tissue, adipose tissue and in the arteries.

When stored, these fatty acids are toxic to tissue cells, which is called lipotoxicity. The same applies to muscle fibers, whereby L-carnitine deficiency leads to muscle atrophy.

What are the sources of L-carnitine in the daily diet?

L-carnitine comes from two important sources for humans:


Meats of animal origin, such as beef, veal, pork, fish, or chicken breast. There are vegetables that contain very small or even zero amounts of L-carnitine, such as carrots or tomatoes, and fruits such as peach, pear and banana.

It should be noted that through food it is never possible to consume the necessary dosage to promote fat burning, so supplementation is the best option.

Table 1. L-carnitine content in foods (taken from FoodData Central of the United States Department of Agriculture -USDA

endogenous synthesis

It is what our own body produces in the liver and kidneys from two essential amino acids: lysine and methionine.

The initial concentration of L-carnitine in newborns depends exclusively on the concentration of L-carnitine in the mother, so women with failures in the synthesis of this amino acid should consume nutritional supplements during pregnancy to ensure the correct concentration in their tissues and in the fetus.

L-carnitine deficiencies in the body

In 1973 the first cases of L-carnitine deficiency in humans were discovered; until then it was believed that it was impossible to suffer from it, from the synthesis and ingestion of it.

However, medical studies detected that some people need L-carnitine nutritional supplements to maintain a normal metabolism, which promoted discussions within scientific societies to consider it an essential nutrient.

So far, that statement has not been reached, but they did identify and classify carnitine deficiency into two large groups:

  • Systemic deficiency that affects the whole body (there are very isolated cases).
  • Myopathic deficiency is the most common and frequent. It affects only muscle tissue.

It is not common to have L-Carnitine deficiencies in the body, but in those cases that exist, they are manifested by muscle fatigue, cramps or premature aging.

Here are some of the known causes of L-carnitine deficiency:

  • Deficiency of the precursor amino acids of L-carnitine: lysine or methionine.
  • Deficiency of other precursor factors such as iron, vitamins C, B3 or B6.
  • Genetic failure in the synthesis of L-carnitine.
  • Intestinal malabsorption.
  • Hepatic or renal problems that affect the synthesis.
  • Defects in the transport of L-carnitine from the liver and kidney tissues of origin, towards the destination ones, which are the muscles where it is used in greater quantities).
  • Increased need for L-carnitine due to a diet that is too abundant in lipids or fats, due to stress, the consumption of certain medications such as anticonvulsants and due to certain diseases.
  • Vegetarian people, since the protein from this source is absent from L-Carnitine.
  • It has been shown that during pregnancy the levels of L-Carnitine in the blood decrease considerably. For this reason, supplements for pregnant women incorporate L-Carnitine as a mandatory ingredient.

The benefits of taking L-carnitine as a supplement

To achieve better results in losing weight and toning muscles, it is recommended to take L- carnitine funcion as a supplement, since a balanced diet does not offer the necessary doses to achieve this effect. But as long as it is accompanied by physical activity or exercises.

If you don't have enough carnitine in your body, the opposite effect will occur: less energy and increased fat tissue.

The benefits of taking L-carnitine as a supplement

How much and how to take L-Carnitine?

L-Carnitine is a safe supplement, but it is necessary to know how to use and dose it effectively, without falling into abuse:

  • How much to take:

The recommended amount is between 1000 and 2000 mg. Remember that by consuming more you will not have better results

There is no risk of poisoning in case you exceed the dose, since it is eliminated through the urine and there are no reports of any adverse effects due to excessive intake.

  • When to take it:

30 minutes before physical activity, approximately.

It is advisable to take it in the morning, because studies indicate that the body will synthesize it better and its benefits are used from the first moment.

For athletes, people who exercise or who seek to tone the body, it is recommended to take it between half an hour and an hour before training.

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