As a dietary element, it is integrated into the body by ingestion of animal proteins or by the body’s production, reaching tissues through circulation.

Origin of L-carnitine

L-carnitine, also called (carnis), which represents meat, comes from Latin and was discovered in 1905 by Russian scientists Gulitsch & Krimberg in meat, the muscles of mammals, showing that this element was essential for the functioning of biochemistry. of muscle cells.

What is L-Carnitine?

It is a very small water soluble molecule that interferes with the natural process of generating heat by triggering an increase in temperature, which will later cause “fat burning and fat reduction.”

L-carnitine is a derivative (amino acid) that can be produced in our body or it can be obtained by eating meat. In addition, it is available in the form of a nutritional supplement.

L-carnitine is a carrier of fatty acids in the cellular mitochondria, responsible for the production of cellular energy, but it is also the place where these fatty acids are converted into energy.

L-carnitine supplements are currently on the market by many companies, but not all are reliable as the isolation process is expensive.

For this reason, we will find on the market products that, without mentioning on the label, may contain a mixture of the “L” form and the “D” form, which will obviously influence the final price, but also the results and In the health.

Types of L-carnitine

It is important to note that there are two forms of carnitine: L-carnitine and D-carnitine. Both “Carnitine” are produced during the ” L-carnitine ” synthesis process , but only the “L” form is biologically active.

L-carnitine is the standard biologically active form of carnitine, found in the human body, in food, and in most supplements. We must remember, however, that there are several types of carnitine:


Often called ALCAR or ALC, acetyl-L-carnitine is perhaps the most effective form of carnitine for our brain. It can also be used to treat neurological disorders such as Alzheimer’s disease.

L-carnitine tartrate

This is one of the most common forms found in supplements in sports, due to the speed with its high absorption, (the substance is quickly absorbed into the body).

This type of carnitine (tartar) can be useful in terms of factors associated with exercise, such as inflammation and muscle pain and muscle recovery after physical exertion.

L-carnitine fumarate

It is an amino acid synthesized at the level of all cells, which is found in some nutritional supplements.


This inactivated form can cause a carnitine deficiency in the human body, by inhibiting the absorption of other forms, much more useful at the cellular level.

For most people, acetyl-L-carnitine and l-carnitine seem to be the most effective for general use. However, you should always choose the form of carnitine that is best for your personal needs and to achieve your goals.

The role of l-carnitine in the body

The main role of l-carnitine in the body has to do with mitochondrial function and energy production in cells. In cells, l-carnitine helps transport fatty acids to the mitochondria, where they can be “burned” or consumed for energy.

About 98% of the body’s midnight l-carnitine is found in our muscles, along with small amounts found in the liver and blood.

For general health, mitochondrial functions can help increase the development of mitochondria and lose it in good condition, which plays an essential role in disease and aging in a healthy way.

Elimination of short and medium chain fatty acids from mitochondria On the other hand, carnitine plays an important role in the elimination of short chain and medium chain fatty acids related to the mitochondria.

You have to understand is that the main role of l-carnitine is the transport of fatty acids into cells to be processed, or “burned” in the mitochondria, to produce energy.

How and when l-carnitine is given

Your levels of l-carnitine are influenced by how much you eat and how much energy your body produces. Therefore, it would be a wise decision for vegetarians and vegans to take, of course, on the recommendation of the doctor. The doctor will explain in detail how and when l-carnitine is administered, depending on the needs of each person.

L-carnitine sources

You can get small amounts in your diet by eating meat and fish, nutritionists say. The main food sources of l-carnitine are meat, fish, and other animal products, such as milk. A healthy individual can also produce sufficient amounts of l-carnitine in his body.

Plant foods that contain l-carnitine

Although there are a number of plant-based foods (such as avocado, asparagus, baked bread, whole wheat), which contain l-carnitine, amounts, and these are often up to tens or hundreds of times lower than the amounts that are found in foods of animal origin.

Animal-based foods that contain l-carnitine

The best Food Sources of l-carnitine include:

  • ground beef: 81 mg for an 85 gram serving
  • pork: 24 mg in a serving of 85 grams;
  • fish meat: 5 mg in a 85 gram serving
  • chicken meat: 3 mg per 85 gram serving
  • milk: 8 mg for a 227 ml serving
  • cheddar cheese, Interesting to note is the fact that food sources of l-carnitine have, in fact, the absorption rate is much higher than supplies.

Dietary supplements with l-carnitine

According to one study, 14% is absorbed when the substance is administered as a supplement. It is good for your body to have the ability to produce l-Carnitine naturally from the amino acids methionine and lysine, in the event that the reserves are too low at the moment. For these reasons, l-Carnitine supplementation should be taken only in special cases, for example, if you use l-Carnitine to treat a disease or medical condition.

Get older

Specialists say that older people would benefit from l-carnitine supplements. Research shows that l-carnitine levels tend to skyrocket as a person ages.

In one study, 2 grams of l-carnitine reduced fatigue and stimulated muscle system function in older people. Other research shows that acetyl-L-carnitine may also be helpful, contributing to brain health and brain function as you age.

Diseases or treatments

Specialists also say that the risk of l-Carnitine deficiency is higher in people suffering from diseases such as cirrhosis and kidney disease.

Therefore, a supplement with l-carnitine could be beneficial for patients with cirrhosis or for those with kidney disease. Also, for medical or genetic reasons, some patients may produce too little l-carnitine in the body and thus result in a deficiency.

The primary systemic carnitine deficiency can occur when the protein is responsible for bringing carnitine within the genetic modification suffers cells. This deficiency causes problems with food processing.

Additionally, this rare condition can lead to:

  • low plasma carnitine values;
  • progressive cardiomyopathy or a condition of the heart muscle (myocardium);
  • skeletal muscle myopathy;
  • hipogluc Polo;
  • weakened hip muscles, weakened muscles in the shoulder area, upper arms, legs, neck and jaw.

If left untreated, it is fatal. Symptoms will gradually get worse from childhood to early adulthood.

If carnitine deficiency occurs as a result of other metabolic diseases, this is a secondary carnitine deficiency. Cancer and aging reduce carnitine levels in the body.

Unbalanced nutrition

People who have an unbalanced diet or lack animal products may need to take l-carnitine supplements or may need to eat certain foods fortified with carnitine.

Correct administration of l-carnitine

Sometimes it is not necessary to eat foods rich in carnitine or to take supplements based on l-carnitine because the liver and kidneys produce enough carnitine for our body.
However, there are people who produce very little carnitine in the body. In your case, your doctor may recommend supplements with l-carnitine.

Recommended daily dose of l-carnitine

The standard dose of l-carnitine is 500 mg per day. Although the recommended dosage varies from study to study, there is an analysis regarding the use and dosage for each form of carnitine .:

  • Acetyl-L-carnitine – Dosages for this form range from 600 to 2500 mg per day;
  • L-carnitine tartrate: doses for this form range from 1000 aieu mg per day;
  • Propionyl-L-carnitine: Dosages for this form range from 400 to 1000 mg per day.

Based on an analysis of research in the field, up to 2000 mg (i.e. 2 grams) per day seems like a safe amount for long-term use and is an effective dose for most forms of l-carnitine.

Thyroid hormones also interact with l-carnitine. L-carnitine appears to reduce the way thyroid hormones work in the human body, and if you consider it paramount at the same time as thyroid hormone-based treatment, it could decrease its effectiveness.

The importance of l-carnitine for the body

L-carnitine is an important amino acid, often used as a weight loss supplement. It does, however, have other benefits for the human body in addition to helping to burn fat.

L-Carnitine benefits

In theory, the use of l-Carnitine as a supplement for weight loss and makes sense, as it helps in the transport of more fatty acids in the cells to be “burned” and converted into energy, but it has many other benefits in addition to burn fat in the body.

The role of l-carnitine in burning fat in the body

L-Carnitine is very important for the body because it plays a crucial role in energy production by transporting fatty acids to the cells, that is, the mitochondria. The mitochondria are responsible for the “burning” of these fatty acids (entr), to create energy that can be used by our body.

Regulation of blood pressure

Some studies have shown that l-carnitine has potential benefits for the heart. Hence, it is beneficial for lowering blood pressure and inflammatory processes associated with heart disease. In one study, participants took 2 grams of acetyl-L-carnitine per day. It lowered her systolic blood pressure, an important indicator of heart health and a risk of disease, by nearly 10 points.

Strengthening the immune system

Acetyl-L-carnitine, say foreign experts, which improves immune function. It is well known that acetyl-L-carnitine can improve the function of the immune system by stimulating the capacity of macrophages (cells of the immune system, the role of important, which are derived from certain white blood cells).

To function as phagocytes (cells in the blood that defend the body from infection, digest and foreign elements, which have entered it).

Cholesterol reduction and triglyceride freedom

A study published in 2009 in “the American Journal of Clinical Nutrition” examined the effects of l-carnitine supplements on oxidized low-density lipoprotein (or LDL-cholesterol oxidation), in the case of patients with diabetes.

The participants were divided into two groups, and the results showed that the l-carnitine-treated eticians had reduced levels of oxidized LDL cholesterol. Also, triglyceride levels have dropped. This study suggests that l-carnitine can keep cholesterol levels in check.

The role of l-carnitine in the growth of bone density

L-carnitine supplementation in the diet improves bone mineral density, an animal study shows. Results from the August 2008 study show that carnitine supplements slow the loss of bone density and improve microstructural properties.

Researchers have also found that l-carnitine can influence bone density and reduce the rate of bone turnover in laboratory mice, leading to differences in the treatment of osteoporosis.

Increased resistance to pain and exertion

Carnitine is used by many athletes and gym enthusiasts, and it is also available as supplements. One reason that convinces many of us to use l-carnitine is that it improves exercise performance in healthy people through different mechanisms.

Other reasons to supplement with l-carnitine have to do with the fact that it increases resistance to pain and exertion to change the way the body responds to physical training, to change the resistance of muscles to fatigue, improves the tolerance to physical activity, increases the resistance of the respiratory muscles.

Fight Male Infertility by Increasing Semen Quality L-carnitine also has benefits in treating sexual dysfunction, experts say.

Two forms of carnitine (propionyl-L-carnitine and acetyl-l-carnitine) enhanced the effectiveness of the drug viagra in terms of restoring sexual potency.

Studies of infertility in men have suggested that 2 to 3 grams per day of carnitine for 3 to 4 months can increase sperm quality and that 2 grams per day, taken for 2 months, can increase sperm motility. But we should note that other studies have not confirmed this, so opinions are divided.

Contribution of l-carnitine in the treatment of cardiovascular diseases.

A 12-month study showed a reduction in heart failure and death among participants who took l-carnitine supplements.

Improved mental status and cognitive decline

L-carnitine may also have benefits in terms of brain function. Some animal studies suggest that acetyl-l-carnitine (ALCAR) may help prevent age-related cognitive decline and improve learning markers.

In human studies, daily administration of acetyl-l-carnitine has helped improve brain function in those with Alzheimer’s disease and other diseases that affect the brain.

Contribution to the treatment of severe kidney disease

For severe kidney disease, experts have found that l-carnitine may have benefits.

The American authorities have approved L-carnitine for the treatment and Prevention of L-carnitine deficiency among patients with severe kidney disease, who undergo hemodialysis.

Improved liver function

L-carnitine supplements improve liver function in those suffering from fatty liver disease (fatty liver disease).

Italian researchers found in 2010 that l-carnitine supplements can improve liver function, liver histology, and other manifestations of nonalcoholic steatosis of the liver (NASH). Supplementation with l-carnitine induces regression of noncohepatitis (NASH) even when plasma and liver carnitine levels appear to be normal, the 2010 study showed.

Adverse reactions of l-carnitine administration

Although experts from around the country from the National Institutes of Health (NIH) say that the quality of the therapy, l-carnitine is “generally safe and well tolerated.”, Supplements with l-carnitine can cause some side effects when they exceed the dose recommended by the specialist.

Ellie Lauderdale

My name is Ellie Lauderdale, MD and I am USA based professional Nutritionist .

I am a Registered Dietitian Nutritionist and board certified specialist in sports dietetics who is trained in integrative medicine. I have worked with hundreds of clients, from those suffering with chronic disease to professional and olympian athletes. My goal is to help optimize you from the inside so that you can feel, perform, and look your best on the outside.

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