If you are a fitness enthusiast, you have probably heard the words “L-carnitine” more than once. This supplement is popular among those who want to lose weight, but few really know all the secrets behind it. Read on to find out the whole truth about this “fat-burning” supplement.

L-carnitine is a compound that increases our bodies’ energy consumption. This means both weight and fat loss. Our body is capable of making this molecule on its own. However, stress, a vegan diet, or excessive fat intake can cause a deficit of L-carnitine.

Key Facts

  • L-carnitine is a fatty acid transporter, it allows fats to enter the mitochondria for oxidation.
  • L-carnitine is essential to synthesizing energy at a cellular level. Its deficit will result in fatigue and muscular weakness.
  • It has been observed that the supplementation of L-carnitine is positively correlated to increased fat loss in obese or overweight people.

Ranking: The best L-carnitine supplements on the market

In the fitness industry, L-carnitine is a very popular supplement. The search for the perfect product can take hours. If you also happen to be vegan or are looking for a quality product, this task will seem impossible. To help you save time, we have rankedthe five best L-carnitine supplements available to you:

No. 1: EBYSU, L-carnitine (180 vegan capsules, gluten-free & non-GMO)

EBYSU is an American company devoted to creating premium supplements made in the USA. This product uses vegan and non-GMO capsules that are also gluten free. Their capsules contain 1,000 mg of L-carnitine each, and two should be taken half an hour before exercise.

Buyers consider it great value for their money. Some people find that “…it is the best cost-to-dosage of any carnitine supplement…”. In general, consumers noticed an increase in endurance when it came to physical activities, creating a positive correlation to achieving their weight loss goals.

No. 2: Evlution Nutrition, L-Carnitine (20 servings, stimulant free)

This is the first BCAA formula with 2 full doses of leading stimulant-free fat-burners that also support building lean muscle. Each dose contains 5 grams of premium BCAAs, 500mg of CLA, and 500mg of L-carnitine while still remaining sugar and gluten free. The manufacturer recommends mixing one spoon of this product with 10-12 oz of cold water during and post training.

Most users give this product great reviews and give kudos to the taste. This supplement of Evlution Nutrition has endowed its consumers with greater edurance, which in turn has helped them lose weight. Even the most skeptical buyers have noticed a difference in endurance that can’t simply be explained by the “placebo effect”.

No. 3: RSP, Liquid L-carnitine 3000 (31 servings, stimulant free)

This supplement contains 3,000 mg of L-carnitine preserving, a very high amount of this product. The manufacturer recommends taking only one serving per day, between half an hour and one hour before exercise. Even without containing stimulants, this is still a very potent supplement. RSP nutrition liquid L-carnitine is thoroughly tested for quality and consistency and manufactured in a GMP certified facility.

Buyers love this product because it works. The majority of users claim to face their workouts at the gym with much more vigor and energy than before. Since it doesn’t contain stimulants, there are no side effects like anxiety or tachycardia. The only negative criticism we find is regarding its flavor – some find it to be somewhat unpleasant.

Shopping Guide: Everything you should know about L-carnitine

Obesity is an epidemic increasingly prevalent in developed societies. Experts work tirelessly on the search for molecules that favor weight loss. Among these substances we find L-carnitine, a fat transporter that can be synthesized by the body or ingested as a supplement.


“L-carnitine is very useful for athletes who practice strength excercises.”(Source: Media Ltd: 42333926/13rf.com)

What is L-carnitine exactly?

L-carnitine is one of the states of the carnitine molecule. This substance takes its name from the Latin “carnis” (meat), since it was discovered for the first time in muscle tissue. Our body is able to synthesize it from the amino acids lysine and methionine. It is abundant in the muscles and heart tissue.

Most guides refer to L-carnitine as a “fat-burning” supplement. The reality behind it is more complex. This molecule binds to the cellular fatty acids and transports them to the mitochondria, where they are transformed into energy. The concentration of carnitine in our body dictates the amount of fat we are able to “burn”.


Combining L-carnitine with caffeine can produce a boost in calorie burn.(Source: Media Ltd: 79189510/123rf.com)

Initially, having a carnitine deficit was considered to be “impossible” due to the body’s ability to synthesize it from other amino acids. However, vegans, people under stress, and people with insufficient micronutrients can suffer from deficiencies of this molecule. This deficiency affects mostly muscle tissue.

Who is at risk of suffering from an L-carnitine deficiency?

Under normal circumstances L-carnitine is synthesized by the liver and kidneys. Its lack is determined mainly by genetic, dietary, or pharmacological alterations. If we leave aside genetic defects (which require follow-up and medical treatment) we find low levels of carnitine in:

  • Vegans y vegetarians: Vegetable products contain less carnitine than animal products.
  • People who follow “miracle” diets: These diets don’t offer a sufficient supply of nutrients, predisposing diet followers to suffer nutritional deficits.
  • Women with Polycystic Ovarian Syndrome (PCOS): Some studies have found low levels of carnitine in these women.
  • People under great stress: L-carnitine is used to defend against the effects of stress, lowering it’s levels the system.
  • High performance athletes: Exercise at high intensities creates stress in the body, this can deplete the reserves of L-carnitine.
  • People who follow certain medical treatments: Valproic acid, for example, has been linked to people with low levels of L-carnitine.

What are symptoms of an L-carnitine deficiency?

A decrease in L-carnitine levels can take place at the muscular or systemic level. A person who is not fed correctly or who is under stress will often develop a muscle-type deficiency. Deficiencies that affect the entire organism (systemic) are much rarer and have serious consequences.

  • Deficit of L-carnitine in musculature: This will cause muscle weakness, fatigue, muscle aches after exercise and swelling in the lower limbs (edema).
  • Systemic deficiency of L-carnitine: This will produce less specific symptoms, such as irritability and lack of concentration. If left untreated, it will eventually cause heart and liver damage.

It is also possible to categorize an L-carnitine deficiency into primary and secondary deficits. Primary deficits prevent the creation of the molecule and affect the individual from birth. If L-carnitine losses increase or production reduces for any reason, we are then talking about secondary deficits.


Vegans and vegetarians may suffer from low levels of L-carnitine. This can negatively affect their athletic performance.(Source: Kachmar: 114134420/ 123rf.com)

What benefits does L-carnitine offer?

L-carnitine functions as a transporter of fatty acids into the cellular mitochondria. There, they oxidize as an ATP molecule. ATP provides the necessary energy for all chemical reactions in the body, especially in the brain. L-carnitine promotes brain function and protects neurons from oxidation.

Because levocarnitine favors the transport of fatty acids to oxidation, it is considered to play a positive role in fat elimination. This transporter can promote weight loss by increasing energy production at the expense of fat metabolism. In addition, several studies argue that the intake of L-carnitine can also lead to reduced appetite.


L-carnitine is not only useful to athletes, it can also help people who suffer from obesity.(Source: Kapura: 114761499/123rf.com)

Levocarnitine is especially appreciated by highly active individuals. By favoring the production of energy, this substance seems to increase aerobic resistance. It also reduces the levels of lactic acid build up in the muscles and has antioxidant functions. This all helps accelerate muscle recovery after physical exertion.

Which foods contain high levels of L-carnitine?

We can increase our levocarnitine levels through nutrition in two different ways. First, we can increase the intake of foods rich in carnitine. As an alternative, we can consume foods rich in lysine and methionine; these are essential amino acids that allow our body to synthesize the fatty transporter.

  • Carnitine-rich foods: Veal, whole milk, blue fish, poultry, cheese, whole grain bread and asparagus.
  • Lysine-rich foods: Cheese, yogurt, butter, soy products, legumes, pumpkin seeds, nuts, quinoa and seitan.
  • Methionine-rich foods: Lamb meat, pork, poultry, eggs, whole milk, yogurt, baked beans, blue fish, soybeans and soy products.

Someone who follows a balanced diet will maintain optimal levels of L-carnitine naturally. However, carnitine comes mostly from animal products, such as meat and dairy. Vegetarians and vegans will have to consume sufficient amounts of lysine and methionine if they want to avoid a deficiency in carnitine.


L-carnitine is predominately used by athletes.(Source: Poplavsky: 74801014/123rf.com)

Who can benefit from L-carnitine supplementation?

In general, there are four groups that can benefit from levocarnitine supplementation:

  • People who are overweight or obese.
  • Athletes who want to increase their aerobic endurance.
  • Vegans or vegetarians with restrictive diets.
  • People who wish to increase their mental performance.

Average-sized people who were supplemented with L-carnitine showed no significant reduction in weight, while a slimming effect was seen in people who were overweight or obese to begin with. Thus, levocarnitine will be useful if your BMI is greater than 25. Unfortunately, it will not help you with localized fat (belly, thighs, and buttocks).

The Body Mass Index (BMI) relates the size and weight of an individual to estimate their nutritional status. A BMI less than 18.5 indicates malnutrition. A BMI that is between 18.5 and 24.9 corresponds to a normal weight. A BMI greater than 25 indicates overweight.

The effects of levocarnitine on mental function were discovered by supplementing alcoholics and elderly people with neuronal impairment. Levocarnitine was able to partially reverse these disorders. Depending on your personal situation, this substance could help you recover your intellectual function.

What is the recommended dose for L-carnitine supplementation?

We are able to absorb between 75% and 80% of the carnitine present in food. In addition, the liver and kidneys can synthesize more L-carnitine if necessary. If we follow a balanced diet rich in various nutrients, we will not need to add a specific daily intake of l-carnitine.

However, we can only absorb 15% of the L-carnitine contained in supplements. Therefore it is important to choose a high dose of levocarnitine. A daily intake of 20 mg of this substance is recommended per 2 lbs of body weight, which is equivalent to 2-4g. This amount should be consumed in two or three doses throughout the day.

Dr. Fernando NaclerioDoctor in Sports Science

“For athletes or active people, doses of 2 to 3 grams per day are recommended, spread out in equal portions throughout the day (take about 1 gr with breakfast, lunch and before training.”

When and how should I take my L-carnitine supplement?

Experts have studied L-carnitine for years. Although this transporter increases energy expenditure and improves sports performance, it is difficult to increase its concentration in the muscle. If you want to get the most out of your levocarnitine supplement, we suggest you follow these recommendations:

  • When? Take 1-2 grams of L-carnitine about 3 hours before your training. Or, take a double dose (2-4 grams) immediately before physical activity.
  • How? As a complement to high physical activity. Stimulation through exercise is necessary to take advantage of L-carnitine. Use it as a complement to your favorite activity.
  • After fasting? Some experts recommend fasting before supplementing l-carnitine to increase absorption. However, adding fruit juice or foods rich in glucose will produce a “peak” of insulin that will increase your muscle concentration.
  • Timeline? The beneficial effects at the muscular level will appear after about three weeks of daily supplementation.

What are the types of L-carnitine supplements available to me?

L-carnitine is available orally and intravenously. In this guide, we strongly advise you to choose the oral form of this supplement. The intravenous route is only used in the medical field to treat serious conditions such as epilepsy and angina. In healthy people, this route is extreme and not recommended.

As for the oral route, you can find over-the-counter supplements with a high concentration of L-carnitine. Generally, these products contain about 500-1,000 mg per serving. Higher doses are limited to the medical field, for the treatment of thyroid, cardiac and male infertility pathologies.


A 12 month study of evolution showed a decrease in heart damage, and deaths from this cause, in individuals who supplemented with L-carnitine.

What are potential side effects of consuming L-carnitine?

As long as the manufacturer’s instructions are followed, L-carnitine is a safe supplement. Healthy volunteers were administered high doses (3gms) for several days, an showed no side effects. In another experiment, nausea and upset stomach were found as the only adverse effects.

Some studies have linked the consumption of L-carnitine to a higher frequency of atherosclerosis. Others, however, have found no relationship between this supplement and arterial hardening. If you are worried about the state of your arteries, consult your doctor and monitor your cholesterol levels.


Your doctor can help you decide if an L-carnitine supplement is appropriate during your pregnancy.(Source: Auremar: 14205474 /123rf.com)

A deficiency of L-carnitine during pregnancy is dangerous, both for the mother and the fetus. So far, no adverse effects on the baby have been reported due to the intake of L-carnitine by the mother during pregnancy. However, you should not take any supplements during pregnancy without the prior approval of your family doctor or midwife.

What differentiates the varied forms of L-carnitine available out there?

L-carnitine is a “stereoisomer” of carnitine, a mirror image of the original molecule (carnitine). We can find this molecule in different formulas, such as D-carnitine and acetyl-L-carnitine. In the following table, you can check the differences between various forms in presentation of L-carnitine:

    Molecule Primary function Applications Side effects
    L-carnitine (levocarnitine) Fatty acids transporter Weight Management, antioxidant and increased aerobic capacity stomach pain, nausea
    Acetyl-L-carnitine (ALCAR) Neuroprotector Cerebal antioxidant. Treatment for depression, parkinson and fibromyalgia. Nausea, vomiting, headache, insomnia, hypertension, hyperglycemia and mental disorders.
    L-carnitine tartrate (LCLCT) Fatty acids transporter As L-carnitine it increases post-training recovery capacity. Nausea, vomiting, diarrhea, gastroesophageal reflux and seizures.
    Glycine propionyl-L-carnitine Energy production and vasodilation circulatio deseases and post cardiac arrest treatment. Nausea, vomiting, tightness and chest pains, generalized weakness.
    D-carnitine (dextro carnitine) Inactive N/A Blocks the actions of L-carnitine.

When choosing an L-carnitine supplement, you will come across many molecules with complex names. Most of these chemicals are more useful for medical practice than for supplementation. The side effects of the other derivatives of carnitine make it more advisable to have supplementation monitored by a doctor.

The simplest form of carnitine is probably the most recommended. Used conscientiously, levocarnitine is safe and its side effects are reduced to gastrointestinal discomfort. Finally, we advise against supplementation with D-carnitine. This form is not active in mammals and its consumption could harm you.

How does L-carnitine compare to slimming pharmaceuticals

Our lifestyle has led many individuals to become overweight. While diet and physical activity are the main remedies for obesity, there are drugs that contribute to weight loss. In the table below you can find out about the main compounds in these drugs:

Product Primary function Slimming effect Side effects
L-carnitine (levocarnitine) Conveyor of fats to mitochondria Mild, it must be accompanied with exercise. Nausea and stomach pain.
Orlistat Inhibitor of fat absorption Moderate (-5 cm waist in 6 months). Allergic reactions, anxiety, diarrhea, colic, gas, incontinence.
Sibutramine Appetite inhibitor High Hazardous: cardiovascular effects and banned in Canada since 2010.
Rimonabant Appetite inhibitor High Hazardous: psychiatric disorders and banned in Canada.

As you can see, most slimming drugs are accompanied by a series of serious side effects. The two most potent substances have been banned in Canada since 2010.

L-carnitine is a safe option that can help weight loss. Specially when compared to the aforementioned weight-loss drugs.

What is the price range in L-carnitine supplements?

There is no doubt about the growing popularity of L-carnitine. That is why its price is somewhat higher than that of other food supplements. The price of L-carnitine tablets or capsules falls around 30 dollars. The same supplement in liquid form is close to 50 dollars per container.

Normally, a package of L-carnitine capsules or tablets will contain about 120 tablets. A single purchase allows you to supplement for two months. The liquid vials come in boxes of 20 units, forcing you to buy it frequently. However, the liquid form of L-carnitine is better absorbed which can justify its price.

Purchase Criteria

Choosing a good L-carnitine supplement can be difficult. There are hundreds, if not thousands, of items that contain varying amounts of this substance. We advise you to keep the following points in mind when making your purchase. That way you will be sure to receive a product that suits your needs:

  • Allergens
  • Pharmocoligal interactions
  • Vegan or vegetarian nutrition
  • Method of ingestion
  • Caffeine content
  • Value for your money


L-carnitine is an essential nutrient for the body. Our body is capable of producing it so the appearance of an allergy would be very rare. However, allergies to the excipients of the supplement have been reported. If you are allergic to lactose or gluten, be especially careful with these supplements.

Pharmacological interactions

L-carnitine can cause drug interactions. This supplement may increase the activity of anticoagulant medications (such as Sintrom). It can also reduce the potency of thyroid hormones. If you are taking medication for these conditions, consult your doctor before supplementing.


L-carnitina L-carnitine supplements are particularly useful to athletes.(Source: Gigowska: 79415148/ 123rf.com)

Vegan or vegetarian nutrition

The name of this supplement, L-carnitine, may make you believe that it is not a suitable product for vegans or vegetarians. Nothing is further from the truth! There are levocarnitine supplements of vegetable origin, which will help vegans and vegetarians get an optimal supply of this transporter.

Dr. Joel KahnCardiologist

“I recommend supplementing vegan nutrition with 500 mg [of L-carnitine] per day to maintain optimal health, particularly those who are athletes or have heart disease.”

Method of ingestion

L-carnitine supplements for oral intake can be sold in different forms of administration:

  • Tablets: Levocarnitine is given in solid form, with coated tablets. They have a pleasant flavor and are easy to swallow.
  • Softgels: L-carnitine is found in liquid form inside these easy-to-swallow capsules. The absorption is fast. Most capsules are made of gelatin, of bovine origin. They are not usually suitable for vegans.
  • Powder: This is an easy format to measure and swallow. It can be mixed with water, juice or milk. If it is not mixed properly, it will create lumps that will hinder intake.
  • Liquid: A truly versatile form of this supplement. Its absorption is the fastest, it is easy to swallow and there are single-dose formats that allow it to be transported anywhere. However, it is the most expensive option.

Caffeine content

Caffeine is a stimulating substance, which reduces appetite and activates the metabolism. Some studies show that combining it with L-carnitine enhances the fat transport function and increases the production of energy. However, if this substance causes insomnia or anxiety, it is better to choose a supplement without caffeine.

Value for your money

It is true that liquid L-carnitine is absorbed more quickly. However, its price is much higher compared to the solid form of the supplement. Remember that the beneficial effects of this product are obtained after several weeks of use. In the end, it will be the constant use of this supplement that benefits your metabolism and creates long term change.


L-carnitine is a fatty acid transporter that favors the creation of energy in our body through fat oxidation. This, added to its antioxidant effects, makes it an ally to weight loss and maintaining good health. Do not underestimate its usefulness when it comes to recovering from a hard training session at the gym!

We hope that the information in this guide allows you to use L-carnitine effectively. Remember that if coupled with a healthy diet and an active lifestyle, this supplement can help you achieve your fat loss goals. Remember to stay away from more dangerous drugs and choose this safe and researched substance.

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(Source for featured image: Trojanowski: 88972439/123rf.com)

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