Last updated: September 10, 2021

Our method

23Products analysed

26Hours spent

9Evaluated articles

85User reviews

If you're into fitness, you’ve probably heard about L-carnitine. This supplement is known to those looking to lose weight, but there are actually several other benefits it has. Read on to learn the full story about this “fat burning supplement”.

L-carnitine is a compound which makes our body use more energy, and therefore causes us to burn more fat. It is an amino acid that is naturally produced in the body, however stress, a vegan diet or excessive fat intake can lead to deficiency.

Key Facts

  • L-carnitine is a fatty acid transporter. It allows fats to enter the mitochondria to be oxidized.
  • L-carnitine is essential for the production of energy at a cellular level. Deficiency produces fatigue and muscle weakness.
  • L-carnitine supplements have been shown to assist with fat loss in overweight or obese people.

Our Selection: The Best L-Carnitine Supplements

L-carnitine is a very popular supplement within the fitness industry as well as with people looking to lose weight. With so many options, finding the best product can be very time-consuming. If you’re vegan or looking for a quality product, the search can be almost impossible. To help you save time, we’ve ranked the best L-carnitine supplements available on the market.

Buyer's Guide: Everything You Need to Know About L-Carnitine Supplements

We know that obesity is an growing epidemic. This has lead to a growing amount of research done to develop supplements that promote weight loss. Among these is L-carnitine, a fat transporter that can be produced by the body or taken as a supplement.

L-carnitine is very useful for athletes who do strength training.
(Source: Media Ltd: 42333926/

What is L-carnitine exactly?

L-carnitine is an amino acid (a building block for proteins) that is naturally produced in the body. It takes its name from the Latin carnis(meat), because 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 in the heart tissue.

L-carnitine helps the body produce energy. It is important for heart and brain function, muscle movement, and many other body processes. It transports long-chain fatty acids into the mitochondria so they can be oxidized (“burned”) to produce energy.

Exercise, L-carnitine and caffeine together can help to accelerate the combustion of energy.
(Source: Media Ltd: 79189510/

This substance because it is naturally produced in the body, so it was originally thought to be "impossible" to have a deficiency. However, vegans, people under stress and people with insufficient micronutrients can  be deficient in this nutrient. This causes weak muscle tissue.

Who is affected by L-carnitine deficiency?

The liver and kidneys produce L-carnitine naturally. Parents can sometimes pass a deficiency down from to their children. Leaving aside genetic conditions (which require medical diagnosis and treatment) low levels of carnitine are also linked to:

  • Vegans and vegetarians: A plant-based diet contains less carnitine than those of animal origin.
  • People who follow "miracle" diets: These diets have insufficient levels of nutrients and can cause a number of nutritional deficiencies.
  • Women with Polycystic Ovarian Syndrome (PCOS): Some studies have found low levels of carnitine in these women.
  • People under stress: L-carnitine is used to combat stress, and therefore prolonged stress can reduce carnitine levels.
  • High-performance athletes: High-intensity exercise puts the body in a stressful situation that can deplete L-carnitine reserves.
  • People following certain medical treatments: Valproic acid, for example, has been linked to low levels of L-carnitine

How does L-carnitine deficiency manifest itself?

Symptoms can happen a bit differently in each person. Children with primary carnitine deficiency tend to show symptoms within the first few years of life. But in some cases, symptoms may start as an adult.

You may also have no symptoms, or your symptoms may be very mild. Some symptoms may appear with skipping meals, a lot of exercise, or illness.

  • Muscular deficiency of L-carnitine: Leads to muscle weakness, fatigue, aching muscle following exercise and swelling in the lower limbs (oedema).
  • Systemic deficit of L-carnitine: Has less specific symptoms, such as irritability and low concentration. If left untreated, it can eventually cause heart and liver damage.

It is also possible to distinguish between primary and secondary L-carnitine deficiency. A primary deficit is a rare condition caused by an abnormal gene. Secondary deficiency is a more common condition. In this case the problem is that there isn’t enough carnitine in the blood. It can result from a number of health problems.

Vegans and vegetarians can suffer from L-carnitine deficit. This will affect their sport performance.
(Source: Kachmar: 114134420/

What are the benefits L-carnitine?

L-carnitine acts by transporting fatty acids to the mitochondria in cells, which then oxidize into an ATP molecule. ATP is vital because it provides the necessary energy for all chemical reactions which occur in our bodies, especially in the brain. Therefore, L-carnitine promotes brain function and protects neurons from oxidation.

More research is needed to confirm the benefits of L-carnitine in a younger, more active population. While it may aid in weight loss for obese individuals or older adults, a thorough diet and exercise regimen must be in place first.

L-carnitine can help overweight and obese people, not only athletes.
(Source: Kapura: 114761499/

Studies in athletes have shown that carnitine supplementation may even boost exercise performance. By producing more energy, it increases aerobic resistance. It also reduces the levels of lactic acid in the muscles and acts as an antioxidant. This aids faster muscle recovery after intense exercise.

How can I increase L-carnitine levels through diet?

Red meat has the highest levels. For example, a 4-ounce beef steak has an estimated 56 mg to 162 mg of carnitine. Alternatively, we can consume foods rich in lysine and methionine, essential amino acids that will allow our body to produce more carnitine.

  • Foods rich in carnitine: Veal meat, whole milk, bluefish, poultry, cheese, wholemeal bread and asparagus.
  • Foods rich in lysine: cheese, yoghurt, butter, soy products, legumes, pumpkin seeds, nuts, quinoa and seitan.
  • Methionine-rich foods: Lamb meat, pork, poultry, eggs, whole milk, yoghurt, baked beans, bluefish, soybeans and soy products.

If you maintain a balanced diet, you should have no problems with your levels of L-carnitine. As you can probably gather, carnitine is in many animal products. This is why vegans tend to get less carnitine from foods, but generally their bodies should produce enough either way.

L-carnitine is especially useful for athletes.
(Source: Poplavsky: 74801014/

Who can benefit from L-carnitine supplements?

There are four main groups who can benefit from levocarnitine supplements:

  • People who are overweight or obese
  • Athletes looking to increase their aerobic endurance
  • Vegans or vegetarians with unbalanced diets
  • Anyone wanting to improve mental performance

People of a healthy weight who take L-carnitine supplements generally do not experience weightless. In contrast, people who are overweight or obese can be found to lose weight with this product. Therefore, if your BMI is over 25, levocarnitine could be useful to you. Unfortunately, though, it will not help to shift localized fat (such as belly, thigh and buttocks).

Body Mass Index (BMI) uses an individual’s the size and weight to estimate their level of health. A BMI of less than 18.5 indicates malnutrition, while a BMI between 18.5 and 24.9 corresponds to a normal weight. A BMI greater than 25 means the individual is probably overweight.

Analysis have shown that alcoholics treated with L-carnitine remained completely abstinent for longer than those without. Scientists have also found significant improvement in Alzheimer’s patients by combining L-carnitine with standard medications used in treating the disease. Therefore, levocarnitine could help you to improve mental functioning depending on your condition.

What is the recommended dose for L-carnitine supplements?

Humans absorb between 75% and 80% of the carnitine in our diet. The liver and kidneys can synthesize additional L-carnitine if required. Healthy children and adults do not need to consume carnitine from supplements, as the liver and kidneys produce sufficient amounts to meet daily needs.

Adults eating mixed diets that include red meat and other animal products obtain about 60–180 milligrams of carnitine per day. The recommended daily intake of levocarnitine is 20 mg per kg of body weight, though our bodies only absorb 15% of what is taken by supplements.

Philip BransenDoctor of Physical Activity and Sports Sciences at Princeton Community Hospital in West Virginia
"The recommended dose of L-carnitine for athletes is 2 to 3 grams per day, and should be taken as two to three doses of the same amount throughout the day and before training."

How and when should I take my L-carnitine supplement?

Carnitine has been studied extensively because it is important to energy production and is a well-tolerated and generally safe. We know it plays a critical role in energy production. If you want to get the most out of your levocarnitine supplement, you’d be wise to listen to the following advice:

  • How? Take L-carnitine to support your fitness. Stimulation is through exercise essential to benefit from L-carnitine. Use it in combination with your sports training.
  • When? One of the best times to take L-carnitine is post-workout, but you can take it with any other high-carb, high-protein meal throughout the day.
  • Should I fast? Some experts recommend using L-carnitine while fasting to increase its absorption. However, fruit juice or foods high in glucose will produce a "peak" of insulin that will increase your muscle concentration.
  • For how long? The beneficial effects at the muscular level will appear after about three weeks of daily supplementation.

What types of L-carnitine supplements are available?

L-carnitine can be taken orally or intravenously. Intravenous L-carnitine is only used in the medical field to treat serious conditions such as epilepsy and angina. t is only recommended to take it orally for healthy individuals.

You can find over-the-counter products with a high concentration of L-carnitine. Generally, these products contain about 500-1000 mg per tablet. Higher doses used in the medical field for the treatment of thyroid, cardiac and male infertility conditions.

A 12-month long study showed a decrease in heart damage and deaths from this cause in individuals who took L-carnitine.

What side effects are there from taking L-carnitine?

L-carnitine is perfectly safe to take as long as the manufacturer's instructions are followed. There are few negative side effects from this supplement at reasonable doses. It can cause nausea, abdominal cramps, vomiting, and diarrhea when taken in high doses.

Rare side effects can include muscle weakness in uremic patients and seizures in people with seizure disorders as well as higher incidence of atherosclerosis. You should keep a close eye on your cholesterol levels under the supervision of your doctor if you are worried about the state of your arteries.

Your doctor should advise you on whether an L-carnitine supplement is recommended during pregnancy.
(Source: Auremar: 14205474 /

L-carnitine deficiency during pregnancy is dangerous, both for the mother and the fetus. Taking L-carnitine during pregnancy has not shown to have adverse effects on the baby during pregnancy. However, it is always essential to consult with your doctor or midwife before taking any supplements during pregnancy.

What is the difference between different types of L-carnitine?

L-carnitine is a "stereoisomer" of carnitine, meaning it is a mirror image of the molecule carnitine. We can find this molecule in two forms, D-carnitine and acetyl-L-carnitine. The following table lets you check the differences between the various forms carnitine:

Molecule Primary function Applications Side effects
L-carnitine (levocarnitine) Fatty acids transporter Weight control, antioxidant and increased aerobic capacity Stomach pain, nausea
Acetyl-L-carnitine (ALCAR) Neuroprotector Antioxidant at the cerebral level. Treatment of depression, Parkinson’s Disease and fibromyalgia Nausea, vomiting, headache, insomnia, hypertension, hyperglycemia and mental disorders
L-carnitine L tartrate (LCLCT) Fatty acids transporter Improves post-training recovery Nausea, vomiting, diarrhea, gastroesophageal reflux and seizures
Glycine propionyl-L-carnitine Energy production and vasodilation Diseases of the circulation and post-infarction recovery Nausea, vomiting, tightness and pain in the chest, generalized weakness
D-carnitine (dextrocarnitine) Inactive None Blocks the effects of L-carnitine

Found in your body, foods and most supplements, L-carnitine is the standard biologically active form of carnitine. D-carnitine is inactive form that may cause a carnitine deficiency in your body by inhibiting the absorption of other, more useful forms if not taken for the right symptoms.

The most effective form for your brain is Acetyl-L-carnitine, often called ALCAR. Studies suggest that it may benefit people with neurodegenerative diseases. Propionyl-L-carnitine is well-suited for circulatory issues, such as peripheral vascular disease and high blood pressure. It may boost production of nitric oxide, which improves blood flow.

How does L-carnitine compare to slimming drugs?

More people are overweight due to our modern society. In fact, figures show that the USA is the most obese country in the world. With the right diet and exercise, supplements can add great value. The following table shows the main compounds that can help with weight loss:

Product Form of action Effectiveness Side effects
L-carnitine (levocarnitine) Transports fats to mitochondria Minor, needs to be accompanied by exercise Nausea and stomach pain
Orlistat Inhibits fat absorption Moderate (-5 cm waist in 6 months) Allergic reactions, anxiety, diarrhea, colic, gas, fecal incontinence
Sibutramine Stops appetite High -
Rimonabant Stops appetite High -

As you can see, most weight-loss medications come with a series of serious side effects.

Compared with these, L-carnitine is a safe option that can assist with weight loss.

Shopping Criteria

There are many different types of supplements out there containing l-carnitine. It is important for you to know which supplement is best for you and will suit your needs. Remember, healthy individuals may not need supplements, or may only need a very small dose. This will help you to find a product for you:

  • Allergies and Intolerances
  • Medication Interactions
  • Vegan or Vegetarian
  • Form of Administration
  • Caffeine Content
  • Value for money

Allergies and Intolerances

L-carnitine produced by our bodies, and is essential to our health. Due to this, allergic reactions to this supplement are very rare. There have been reports of allergies to other ingredients in L-carnitine supplements. If you are allergic to lactose or gluten, you should be particularly careful with these products.

Medication Interactions

L-carnitine may react with prescription medication. For example, this supplement could limit the effectiveness of anticoagulants (such as Sintrom). It may also limit the effects of thyroid hormones. If you are taking medication for any of these conditions, consult with your doctor before taking supplements.

L-carnitine supplements are particularly useful for athletes.
(Source: Gigowska: 79415148/

Vegan or Vegetarian Nutrition

L-carnitine  supplements are of vegetable origin, which will help vegans and vegetarians to improve their levels of this important transporter. Please keep in mind that taking L-carnitine supplements is not essential for vegans and vegetarians, and may not be necessary depending on the individual. This is something to consult with your doctor about.

Joel KahnCardiologist in Detroit, Michigan
"I recommend supplementing vegans with 500 mg [of L-carnitine] per day to maintain optimal health, particularly for athletes or patients with heart disease."

Method of Administration

Oral L-carnitine supplements are sold in different forms:

  • Tablets: Levocarnitine is given in solid form, in coated tablets. They have a neutral flavour and are easy to swallow.
  • Soft capsules: L-carnitine in its liquid state is contained inside these easy-to-swallow and fast-absorbing capsules. Most capsules are made of gelatin, which comes from cows and therefore is not usually suitable for vegans.
  • Powder: In this form, L-carnitine is easy to dose and swallow. It can be mixed with water, juice or milk. If not mixed properly, it can be lumpy and therefore harder to take.
  • Liquid: A very versatile form of the supplement. This is the fastest absorbing, is easy to swallow and comes in single-dose formats making it extremely portable. However, it is also the most expensive way to take L-carnitine.

Caffeine Content

L-Carnitine is stimulant-free. It does not contain anything such as caffeine or other stimulants that are popularly found in other energy supplements and drinks. This is important to note because you can take this any time of day or add it to your current supplement intake.

Value for Money

Liquid L-carnitine is absorbed more quickly. However, it is also much more expensive than the solid form of the supplement. Remember that it take a few weeks to start seeing results with this product. In order to have the desired effects on your metabolism, you need to use it regularly over a period of time.


Most people will go on some new fad diet, add in some cardio to their workout regimen, grab an over-the-counter weight loss miracle pill, or a combination of all of these things in order to lose weight. Now you can buy one supplement that is proven to help you burn off fat by converting it into energy.

We hope that the information in this guide helps you to use L-carnitine effectively. Coupled with a healthy diet and an active lifestyle, this supplement can assist you to achieve your weight loss goals. Stay away from other, dangerous weight-loss medications and choose this safe and recognized supplement instead!

If you liked our guide to L-carnitine, please leave a comment and share this article.

(Source of the featured image: Trojanowski: 88972439 /