L-carnitine: What It Is and How It Works

L-carnitine is released in different forms, such as tablets, capsules, or syrupL-carnitine is released in different forms, such as tablets, capsules, or syrup


Description of the Substance

L-carnitine (levocarnitine) is an amino acid that is naturally produced by the human body to accelerate and improve the metabolism.

It plays an essential role in the conversion of fats into energy. If the body lacks carnitine, it cannot properly process lipids, which results in obesity and heart troubles.

L-carnitine increases stamina and reduces fatigue. It also speeds up the rebuilding of muscles after extreme physical activities and helps to protect fibers from injuries during workouts.

Supplementation of this substance is recommended for athletes of all kinds of sports. It is very effective for those engaged in bodybuilding, fitness and aerobics.

L-carnitine can be used for two main purposes:

  1. As a fat burner for those who wish to lose extra weight (but only in combination with physical exercises).
  2. For the improvement of the immune system and brain functioning.

Discovery of the Substance

Russian biochemists Vladimir Gulevich and Robert Krimberg extracted this amino acid from muscular tissues and mistakenly categorized it as a B vitamin. However, it became clear that the body can produce this substance in the liver and kidneys.

After further carnitine studies, the scientists began to classify it as a coenzyme (a substance necessary for the work of enzymes). This opinion remains the same today.

What Foods Contain Carnitine?

The best sources of this amino acid are the following products (per 100 gr):

  • beef (95 mg);
  • beef steak (94,5 mg);
  • pork (27,7 mg);
  • bacon (23,3 mg);
  • duck (18,4 mg);
  • salmon (10 mg);
  • milk (3,3 mg).

Use for Weight Loss

The usage of L-carnitine for weight loss is effective only in combination with continuous physical activities, such as aerobics, race walking, running, dancing, or other cardio workouts. Otherwise, the effect will be opposite: you will become hungrier. You should train at least 25–30 minutes to burn lipids naturally. The intake of this supplement will help the body produce energy out of fat stores.

At the same time you should consider your nutrition, create a healthy food ration, and avoid diets that cause fatigue.

By reducing your carbohydrate consumption by 10%, you will be able to work them off faster during your workout. As a result, lipid energy production will activate sooner.

For Athletes

As mentioned above, levocarnitine helps athletes protect muscles from injuries that often occur during workouts. The intake of this substance also increases the body’s endurance due to the energy that is released during fat burning.

Using dietary supplements containing L-carnitine in sports nutrition is similar to using them for weight loss, except for dosages and intake frequency.

There are many advantages of levocarnitine supplementation for those who are fond of sports. Levocarnitine:

  • helps to maintain the glycogen stores in the body;
  • reduces hunger, which is especially felt after physical activities;
  • positively influences the cardiac muscle;
  • reduces injuries if taken regularly;
  • keeps the reserves of the BCAA and other amino acids.

At the same time, levocarnitine can be taken together with other fat burners and supplements without any restrictions.

Different Types

At the sporting-goods stores you can find the following kinds of the supplement:

  1. Acetyl-L-carnitine.
  2. L-carnitine fumarate.
  3. Levocarnitine tartrate.
  4. Propionyl-L-carnitine.
  5. Pure carnitine.

The first kind is recommended for the improvement of brainwork, because it reaches the brain easily. The second kind is good for the cardiovascular system.

The third kind easily dissolves in the body and breaks up into tartaric acid and pure supplement. It is mainly used for weight loss. The propionyl carnitine supplement improves the work of blood vessels and helps to prevent cardiovascular disease. In its pure form the supplement is similar to the levocarnitine tartrate.

How to Take It?

At intensive physical loadings the amount of levocarnitine received from natural food can be insufficientAt intensive physical loadings the amount of levocarnitine received from natural food can be insufficient

To begin with, let’s see how much L-carnitine the body needs. The tissues of striated muscles and the human liver contain nearly 25 g of this substance. The body needs 0.2-0.5 g of carnitine daily; at greater physical activity the requirement increases to 1.5-2 g.

L-carnitine can be replenished with a protein-enriched meal. Food such as chicken, fish, cottage cheese, and wheat sprouts contain L-carnitine. Nevertheless, there is not a lot of extra L-carnitine in the body, especially for athletes. Various dietary supplements help to compensate this deficiency.

Dosages depend on the person and his or her characteristics, such as body state, physical activity level, and the chosen supplement. The manufacturers often note indications and usage on the supplement packages, and they should not be neglected.

General Recommendations for Use

Form of presentation Dosage Notes
Syrup 5 ml 3 times per day Athletes should drink the daily dose (15 ml) at one serving 20-30 minutes before training
Tablets and capsules 250-500 mg 2 or 3 times per day For athletes – 500 to 1500 mg at a single dose prior to workout
Powder 1 g per day Large doses (9–15 g per day) are acceptable if necessary (for example, to prepare for sporting events)
Although there have not been any overdose cases or any serious side effects (except for diarrhea provoked by severe irritation of gastrointestinal mucosa), it is worth consulting an expert prior to the supplementation.

The course of liquid L-carnitine administration is 1 or 1.5 months with the possibility of a repeated course in 2–3 weeks. L-carnitine tablets can be used for 2–6 months.

The course can be repeated 4–6 times a year. It is not recommended to use the supplement for more than 6 months. Also, supplements containing levocarnitine should not be used during pregnancy and lactation because of inadequate data for its effect on the baby.

How to Take the Substance in Liquid Form?

L-carnitine is produced in liquid (syrups, special drinks, and ampules) and solid forms (tablets and capsules). The supplement is considered both a dietary supplement, and medicine (Elcar, etc).

Doctors and nutritionists suggest taking the liquid levocarnitine (acetyl-levocarnitine) in the form of vitamin cocktails between meals or 20 minutes before eating. You should not use it on an empty stomach to avoid negative consequences on GI microflora. The supplement should be used before noon (better between breakfast and lunch), because the increased energy production can prevent sleep.

It is useful to take the supplement in liquid form especially before training: the dosage is convenient, the taste is pleasant, and moreover, there is no need to wash it down with water.

At other times capsules or tablets are more preferable. As a rule, the manufacturers seldom produce pure L-carnitine in the liquid state: such supplements often contain sweeteners and flavors. This form of presentation is more expensive in comparison with others.

How to Take the Drug in Tablets or Powder?

L-carnitine tablets and powder are taken generally in the same manner. Pay attention to the content of the substance in one tablet or capsule. Nutritionists suggest washing the substance down with juice or still mineral water.

L-carnitine tablets are absorbed by the body slower than the liquid.

If you want to normalize heart activity, you should choose L-carnitine tablets. If you wish to get rid of extra kilos or if you train hard, use the supplement in the liquid form.

Remember that you should limit the consumption of products containing caffeine during the whole course of supplementation, otherwise it can be stressful for the nervous system.

Common Mistakes

Any dietary supplement must be used properly. The benefit of carnitine will be miserable in the following cases:

  1. If you violate optimal time. The greatest effect of the drug is achieved in 20-30 minutes after its consumption. It lasts for 2 hours. Try to use the supplement 15–20 minutes prior to workout.
  2. If the dose is too small. In this case, more is better than less. Overdosage can cause diarrhea, but it happens rarely.
  3. Carnitine itself does not help to lose weight or keep the body in shape. Therefore, you should not forget about training, and a healthy and balanced diet.

Athletes’ Reviews

Both in network and at the nearest gym it is possible to meet people who use levocarnitine in their workouts. In most cases they recommend this sports supplement; at the same time they note that it will not work if you just sit idly on the sofa.

There are many critics around the world who dispute the action of the drug on an athlete's body. They argue there is no sense to take extraneous carnitine, and any benefits are the result of the supplement manufacturers.

There is no consensus on it. At the same time, there are many examples showing that additional doses of this coenzyme help burn fat and increase stamina. What experience did you have with L-carnitine supplementation? Do you hold the opinion of the critics or agree with the manufacturers of sports nutrition?

Shesternenko Alexander
Fitness trainer, group instructor, dietitian
  • Counsels and educates on proper nutrition principles, body weight correction, and adjustment of individual diets and diets during pregnancy;
  • Develops meal plans that meet nutrition goals and dietary needs for obese and underweight people;
  • Specializes in modern functional testing techniques in sports, athletic recovery, sports supplementation, pharmacological support, and actual women's problems in sports;
  • On the website, provides analysis of different dietary schemes, reviews modern training techniques and effective exercises.


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