Last updated: 17/10/2022

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One of the most common end-of-year wishes and goals at the beginning of the new year, and the reason why people go to the gym, is to burn fat, tone muscles or improve their physical health. But how to achieve these results in addition to a diet and exercise routine?

What to take and which is best? We want you to have all the relevant information to make the best purchasing decision. From benefits and side effects, consumer profiles, to the supply of the supplement on the market.


  • L-carnitine is a natural substance produced by metabolism in the living cells of the body, chemically speaking it is classified as an amino quaternary. Given that its natural sources are very limited, both animal and vegetable, we will discuss the advantages of taking it in supplement form.
  • The main function of L-carnitine is to transport fatty acids to oxidise fat mass and convert it into energy for the body.
  • There are many benefits to be gained from taking this metabolic substance, including functional improvements in organs and tissues such as muscles, heart, brain and skin, metabolising stored fat, and optimising physical performance, among others. In addition, its adverse effects are minor and its incidence is rare.

The Best L-Carnitine: Our Picks

Buying guide

The main function of L-Carnitine is to transport fatty acids to oxidise fat mass and convert it into energy for the body.
(Photo: Media Ltd/

What is L-carnitine and what are the benefits of consuming it?

This substance can be found in the normal diet, but it is never sufficient in this way because the dosage required in the body to promote fat burning and thus provide energy is not sufficient on its own. It is therefore necessary to resort to supplementation. L-carnitine is made up of two essential amino acids: lysine and methionine. In addition, for optimal synthesis, it requires the presence of 3 components in the body: iron, vitamin C and B complex.
  • Metabolisation and elimination of fat
  • Increase in physical and mental performance
  • Reduction of the sensation of fatigue
  • Decrease in the destruction of muscle mass
  • Antioxidant
  • Decrease in cholesterol
  • Body odour
  • Skin rash
  • Diarrhoea and gastritis
  • Nausea or vomiting
  • Insomnia
  • Fever

How is l-Carnitine produced?

L-Carnitine is produced through a biochemical process whose basic function is to transport fatty acids (energy producers other than glucose and amino acids) to every cell in the body. By sending more Carnitine to a higher intake it ensures that storing less fat mass is feasible, which is why many people classify it as a “Fat-burner”. This metabolite has demonstrated multiple benefits not only in metabolising fat, it also aids detoxification and ATP energy release, improves physical and mental performance, is an antioxidant and reduces the feeling of fatigue after intense exercise workouts.

Who can or cannot take l-carnitine?

As we have seen throughout this article, there are many advantages to consuming L-Carnitine, just the fact that it has minor side effects and uncommon cases already gives it a point in favour. At an early age L-Carnitine is a key factor for growth and at an advanced age it optimises and generates longevity. Despite this and the fact that its sale does not require a medical prescription to acquire it, there are profiles of people who are partially or completely limited in their consumption.

It is therefore recommended that you always consult a doctor, nutritionist or specialist before buying it. Its use is common among people of all genders who do high-performance sports, specifically bodybuilders, those undergoing weight and fat loss treatment, and people whose age range is considered advanced due to the natural wear and tear of cells, and patients with metabolic deficiency.

This is not the scenario for patients with hypertension, liver cirrhosis or haemodialysis, pregnant women, nursing mothers or those with peripheral neuropathy, so it is best avoided without medical consultation due to the reactions it may cause with established treatments.

Who can Who can’t
High performance athletes Patients with hypertension
Elderly people Patients with liver cirrhosis
People with metabolic deficiency Patients on haemodialysis
People undergoing treatment to reduce fat mass Patients with peripheral neuropathies
Growing children Pregnant or breastfeeding women

How much does l-carnitine cost?

There is a wide variety of formats and presentations for L-Carnitine on the market. There are capsules, effervescent tablets, powder and even liquid versions such as herbal teas or drinks to choose from. Prices vary depending on the format, the size in which you want to consume it and where you buy it; the most common form is capsules and liquid, ranging from 200 MXN to 500 MXN.

Vegans and vegetarians may suffer from a lack of L-carnitine. This will affect their athletic performance.
(Photo: Kachmar/

Buying criteria: factors that allow you to compare and rate different presentations of L-Carnitine as a dietary supplement

When we start out in the world of fitness or are simply recommended a new product to help us achieve our health goals, it is easy to get into conflict (either because of the nomenclature or the names of these hitherto unknown products). In order to choose the one that best suits you, we want to show you the relevant factors to consider in order to make a good purchase.

L or D?

Carnitine is a molecule with two forms that mirror each other, and are distinguished by preceding the letters “L” and “D”. L- is the active form in the body and D- is the available form, the former being the one we are interested in when looking for it on any shelf or e-commerce. When buying products derived from either amino acids or in this case amino quaternary acids, it is advisable to always look for the L- form, as the body does not require the other.

Your doctor can help you decide if an L-carnitine supplement is right for you during pregnancy.
(Photo: Auremar/

Presentation and dosage

Unlike other supplements such as amino acids or vitamins, L-carnitine is marketed or is more commonly found in liquid form, i.e. drinks or infusions, we recommend you choose this; however the range of presentations varies and there are capsules, effervescent tablets, powder or even bars depending on your preference. There are five advantages to opting for the liquid form:

  • Its absorption is greater and more effective than other formats as it goes directly into the bloodstream.
  • In most cases, it is accompanied by additional ingredients, so it is an integral product.
  • Its concentration is up to 3-5 times higher.
  • There is a variety of flavours to choose from.
  • It is ideal for any age due to its assimilation by the digestive system.

Compared to the other presentations, they are considered to be easier to transport and there are no taste problems to contend with. Doses are different for each individual and vary from small amounts, usually around 50 mg to 500 mg per day, depending on the person’s regular diet, above which it is used for therapeutic effects. Vegetarians need a much higher intake than those who eat meat.

(Featured image photo: Trojanowski/