L-carnitine for weight loss


L-carnitine is a chemical that helps the body turn fat into energy. Since L-carnitine plays a major role in lipid metabolism, it may help people lose weight. 

L-Carnitine Production & Storage

Carnitine is produced by the liver and kidneys. It gets stored in muscle, brain, and heart tissue, all of which use fatty acids as energy.

L-carnitine is made from amino acids lysine and methionine and it plays a critical role in fat degradation to form adenosine triphosphate (ATP), the energy currency of cells. 

L-carnitine has long been thought to promote weight loss due to its effects on lipid metabolism.

L-carnitine transports long-chain fatty acids into mitochondria, an organelle which is considered the powerhouse of cell. The mitochondria is a double sac organelle where glucose and lipids are metabolized to form ATP. 

It is also essential in detoxifying mitochondria by ferrying out toxic compounds and preventing their accumulation in the mitochondria. Hence, L-carnitine protects the mitochondria while also ensuring that it exports sufficient ATP to power up chemical reactions in cells. 

L-carnitine and weight loss: Research 

A systematic review & meta-analyses of 37 randomized controlled clinical trials reported that supplementation with L-carnitine significantly decreased body weight, body mass index & fat mass. A total of 2,292 participants were involved in the 37 randomized controlled trials.

On an average, individuals who took the supplement lost 1.21 kg, with some losing as high as 1.73 kg and others losing merely 0.68 kg. The average body mass index reduction was -0.24 kg/m2, and fat mass reduction was -2.08 kg. 

People enrolled in the clinical trials were taking 2000 mg of L-carnitine supplement daily. Participants taking this amount of supplement experienced significant weight loss but no significant changes in body fat percentage and BMI. 

The study, published in the Clinical Nutrition Espen and led by investigators from University Medical Sciences in Iran, stated that the most significant weight changes were seen in those who were obese or overweight at the beginning of the study. 

The findings of this study have important implications for the use of L-carnitine for weight loss, especially in individuals who are overweight or obese. Since meta-analysis reduces the risk of bias, the results can be used in healthcare practice.

Another systematic review and meta-analysis also proved that L-carnitine supplementation can promote weight loss.

The study, published in the Obesity Reviews journal, analyzed nine randomized controlled trials that involved 911 participants. 

The findings of this review showed that those taking L-carnitine had an average weight loss of -1.43 kg and a reduction in BMI of -0.47 kg/m2 compared with the control group. The subgroup analysis demonstrated that the effects were the greatest in those who were obese or overweight at the beginning. 

Based on these two good-quality reviews, intake of L-carnitine supplement can aid in weight loss. However, a dosage of 2000 mg daily over a long period of time is needed to see significant reductions in weight loss. 

Concerns on prolonged use of L-carnitine from red meat 

While L-carnitine is acclaimed as an essential compound in helping skeletal muscles and heart muscles to use energy from mitochondria effectively, it might influence the development of heart diseases, if taken in excessive amounts.. 

Red meat is the most abundant source of L-carnitine. As a rule, the more red the meat is, the more will be the L-carnitine content. 

About 113 grams or 4 ounces serving size of cooked beef, contains 56 to 162 mg of L-carnitine. This amount of L-carnitine in a serving size of meat makes up 11.2% to 32.4% of the recommended daily allowance (RDA) of this nutrient. 

However, an older study published a decade back, suggests that overconsumption of red meat could lead to cardiovascular diseases. Authors of this study, which was led by Robert Koeth from the Department of Cellular and Molecular Medicine at the Cleveland Clinic in Ohio, explained that the link between ingestion of red meat and cardiovascular disease could be due to the action of intestinal microorganisms. 


The intestinal microbiota which is composed of different microorganisms, metabolizes choline/phosphatidylcholine to a compound called trimethylamine (TMA). The TMA is further metabolized to trimethylamine-N-oxide (TMAO). 

The gut microbiota has been shown to metabolize dietary L-carnitine to TMAO, which then speeds up the thickening of the arterial blood vessels with fatty deposits. This thickening results in atherosclerosis, which is the buildup of fatty deposits in arterial walls leading to coronary heart disease. 

Robert Koeth also cited animal studies which clearly demonstrated that chronic L-carnitine supplementation resulted in increased synthesis of TMAO and of course increased risk of atherosclerosis, stroke and heart disease. 

Based on this study, a moderate intake of red meat is necessary to prevent heart disease or atherosclerosis. Ingesting just one serving size per day is sufficient to increase L-carnitine levels in your body. Eating it through other food sources could also help you reach the required amount of this supplement daily. 

However, if for some reason, it is difficult to reach the required daily allowance by diet, which ranges from 500 to 2000 mg daily, you can take supplementation. However, always talk to your doctor before taking the supplement.

How to support L-carnitine weight loss? 

When supplementing with L-carnitine to lose weight, you can also support this with other strategies known to promote weight loss: 

  • Take a well balanced healthy diet.
    • A Mediterranean diet high in fiber and nutrients from fruits and vegetables and also high in omega-3 fatty acids from fish could be a great in your weight loss journey. 
  • Try intermittent fasting.
    • Intermittent fasting has been known to reduce weight and improve mood significantly. However when taking supplementation, always speak to your doctor when considering intermittent fasting.
  • Walk or run for a minimum 10 minutes daily.
    • Walking is the simplest form of exercise. It has been proven that walking for at least 30 minutes on most days of the week could lead to significant weight loss over time. 

Is it safe to take L-carnitine for weight loss? 

So far, there are no studies suggesting any ill effects of taking a certain required amount of L-carnitine. A dose of up to 2000 mg daily is safe and effective in improving health. Further, overtaking from food sources does not lead to adverse effects.

What are the food sources rich in L-carnitine? 

  • Ground beef
  • Cooked asparagus 
  • Cooked cod fish
  • Chicken breast 
  • Cheddar cheese 
  • Whole wheat bread 
  • Whole milk
  • Pork meat
  • Beef steak

A serving size of these foods is good enough to help you get the daily recommended amount. 

Supplementing with L-carnitine can significantly reduce weight compared with those not taking supplements. However, the average weight loss with this compound is only less than 2 kilograms. Hence, supporting its supplementation with diet and exercise would be the ideal way to achieve your weight goal. 


Research studies have suggested that taking L-carnitine supplements may help you lose weight. However, the recorded weight loss from these studies was, on average, less than 2 kilograms. It should be noted that the supplementation in the studies was only for a few weeks or months. It is still being determined if the weight loss effects could be sustained over time or whether more prolonged supplementation would lead to more weight loss

My name is Amanpreet Kaur Samra. M.S. Biochemistry. I'm the founder and writer of this blog. I have been teaching Biochemistry for a good number of years. I started this blog because I have always been very passionate about writing, in particular about Nutrition and Healthy Weight Loss.

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