How Does Carnitine Work to Burn Calories?

How Does Carnitine Work to Burn Calories?

Our bodies require an organic compound called carnitine to function correctly. Muscle weakness, brain dysfunction, and other severe symptoms can occur without it. Luckily, the production of carnitine is a natural process that happens on its own, but research reflects that increasing carnitine intake can have great health benefits including antioxidant properties and potential weight loss. 

What is Carnitine?

Let’s start with what carnitine is, a substance derived from the amino acids methionine and lysine. Carnitine is made in the brain, liver, and kidneys, but is stored mostly in the skeletal muscles and the heart. The richest sources of carnitine are meat, fish, poultry, and dairy, but it’s also in fruit, vegetables, and grains in smaller amounts. Considered a “conditional” essential nutrient because under certain circumstances the body’s requirements may exceed its capacity to synthesize it [1]. 

Carnitine plays a vital role in energy production as it assists in transporting long-chain fatty acids to the cell’s mitochondria to be oxidized into adenosine triphosphate (ATP) [2]. There are many forms of carnitine, each with its own specific uses. The most common form, and the one we will focus on, is L-carnitine. Other forms of carnitine are:

  • Acetyl-L-carnitine: used for brain disorders like Alzheimer’s disease because it possesses neuroprotective properties to safeguard the nervous system.

  • Propionyl-L-carnitine: commonly used in heart-related research for conditions such as heart disease and peripheral vascular disease. It also has pain-relieving and antirheumatic properties.

  • D-carnitine: this form of carnitine is toxic to the body and may inhibit the absorption of other carnitines.

  • L-carnitine L-tartrate: this is what you’ll find many athletes using because it may prevent muscle weakness and exercise fatigue [3]. 

  • L-Carnitine Benefits 

    L-carnitine, and carnitine in general, is a direct contributor to the metabolic process and offers numerous benefits. First of all, it saves other amino acids as energy sources during exercise. This can allow for protein synthesis and a decrease in lactate accumulation. In other words, L-carnitine works to fight muscle fatigue and may encourage an increase in muscle size. Not only that but having an increase in L-carnitine preserves glycogen stores and promotes fat oxidation. 

    Fat oxidation provides energy to increase athletic performance. However, it also means it targets fatty acids, which means breaking down fat. But does carnitine truly result in weight loss? 

    One study found in a 12-week trial that it can be a contributing factor in fat burning. Half of the study’s male participants took a carnitine supplement and drank a carbohydrate beverage twice a day. The other only took the carnitine. Researchers found that the subjects that had the carbs in addition to carnitine gained an average of four pounds. The supplement group didn’t gain any weight. In addition, the participants also did 30 minutes of low-intensity exercise and the findings showed an increase in calorie burning linked to an increase in fat metabolism [4]. 

    Aside from weight loss, L-carnitine has antioxidant properties that make it suitable for treatments of brain diseases and heart conditions, too. 

    What is the Right Dosage of L-Carnitine for Weight Loss?

    For weight loss, research suggests L-carnitine L-tartrate is the best form because it increases athletic performance. Safe doses range from 1,000 to 4,000 a day [5]. On its own, carnitine is not going to cause you to drop a ton of weight. Rather, it works best when paired with a proper diet and exercise. 


    1. U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - carnitine: The science behind a conditionally essential nutrient - conference summary. NIH Office of Dietary Supplements. Retrieved March 31, 2023, from,is%20excreted%20via%20the%20kidneys.  
    2. U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - carnitine. NIH Office of Dietary Supplements. Retrieved March 31, 2023, from  
    3. MediLexicon International. (n.d.). L-carnitine: Types, benefits, and side effects. Medical News Today. Retrieved March 31, 2023, from  
    4. Carnitine (L-carnitine). Mount Sinai Health System. (n.d.). Retrieved March 31, 2023, from  
    Mawer, R. (2023, March 27). L-carnitine - a review of benefits, side effects and dosage. Healthline. Retrieved March 31, 2023, from 

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