Nutritional supplements containing L-carnitine have become popular in recent years for improving athletic performance and promoting weight loss, in addition to other medical uses.
But what exactly is L-carnitine? How does it work in our body? And above all, is it really effective in all your applications? In this article, we’ll answer these questions.
What is L-carnitine?
Carnitine is an amino acid produced by the kidneys and liver and which is stored in the brain, heart, muscles and semen. It participates in the transformation of fat 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.
Carnitine it is mainly found 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 a low concentration of this amino acid in some vegetables and grains as well.
This compound is used as a supplement to treat various disorders of the body and to improve metabolic activity. However, not all of its applications have been approved by scientific research.
How does it act on the body?
L-carnitine is used to transport fatty acids across the mitochondrial membranes of cells. The enzyme carnitine palmitoyltransferase binds L-carnitine molecules to fatty acids.
This amino acid has antioxidant effects: Eliminates free radicals, particles which, if accumulated in excess, alter DNA and damage cells by oxidation, and can promote the development of cancer.
L-carnitine deficiencies can occur in the body due to genetic alterations or malnutrition, as well as the exclusive consumption of plant foods.
Lack of L-carnitine can cause various alterations depending on age, severity and the organs involved. Some of the most characteristic symptoms of this disorder are a decrease in glucose levels (hypoglycemia), the onset of disease of the heart muscle (cardiomyopathy), and fatigue.
What is this for?
The uses of L-carnitine as a nutritional supplement are manifold, although all of its purported benefits have not been demonstrated and much remains to be studied. In this section, we will detail the scientific evidence regarding the different applications of this substance.
Under no circumstances is it recommended to take L-carnitine supplements without a prescription as it is an investigational drug in most of its applications.
1. Kidney disease
The kidneys are involved in the production of L-carnitine, so the blood levels of this amino acid they are affected in kidney disease. This is where external L-carnitine is most effective.
L-carnitine supplements have been shown to be effective as an adjuvant for people on hemodialysis, a form of therapy that replaces kidney function when not working properly. This not only reduces the symptoms of L-carnitine deficiency, but can prevent them as well.
2. Cardiovascular disorders
Scientific studies have found preliminary evidence in favor of the use of L-carnitine in heart disease and the circulatory system in general.
Specifically, L-carnitine it can increase the capacity for physical exertion people diagnosed with angina or heart failure, as well as reducing the risk of death after a heart attack 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 lowering cholesterol and triglyceride levels.
3. Weight loss
There is not enough scientific evidence to claim that L-carnitine is effective as a weight reduction supplement, although this is one of its most famous applications.
Some studies claim that this compound reduces fat accumulation and increases muscle mass. In addition, the effects of L-carnitine on reducing fatigue indirectly facilitate weight loss.
4. Male infertility
Male infertility has been linked with low levels of L-carnitine. According to research, supplements of this amino acid are likely to increase the number and mobility of sperm.
Box of L-carnitine help regulate blood sugar people with diabetes if they are taken in addition to a specific medicine to treat this disease.
Likewise, it may be effective in reducing symptoms of diabetic neuropathy, which occurs when high levels of glucose damage nerves in the limbs, causing pain and numbness.
Carnitine seems to reduce symptoms of hyperthyroidism, A disorder characterized by an excessive secretion of thyroid hormones. Studies in this regard are promising but currently inconclusive.
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 may increase the effectiveness of Viagra in impotence, especially in men who do not respond adequately to this medication and who have had prostate surgery.
There is preliminary scientific evidence on the usefulness of L-carnitine for reduce age-related fatigue, Cancer, celiac disease, hepatitis, multiple sclerosis and chronic fatigue syndrome, as well as fatigue in general.
9. Sports performance
Strenuous exercise has been linked to decreased levels of L-carnitine, hence many athletes use these supplements to improve their performance. However, and although some studies support this hypothesis, it cannot be said that L-carnitine is useful in improving athletic performance.
- Steiber A., Kerner J., Hoppel CL (2004). Carnitine: a nutritional, biosynthetic and functional perspective. Molecular aspects of medicine. 25 (5-6): 455-473.
- Vaz FM, Wanders RJA (2002). Biosynthesis of carnitine in mammals. Biochemistry. J. 361: 417-429.
- Wall BT, Stephens FB, Constantin-Teodosiu D., Marimuthu K., Macdonald IA, Greenhaff PL (2011). Chronic oral intake of L-carnitine and carbohydrates increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. PubMed.gov.