Carnitine, or L-Carnitine, is claimed to increase fat metabolism, and is included in many weight loss supplements. How accurate are these claims? We’ve searched several reputable medical sites for information on this supplement, in search of the answer.
According to Health and Age:
Muscular activity depends on your body’s ability to convert fatty acids into energy. Carnitine is an amino acid that is essential for this conversion. A typical daily diet contains 5 to 100 mg of carnitine. The body produces carnitine in the liver and kidneys and stores it in the skeletal muscles and heart, as well as in sperm and in the brain.
Some people cannot properly use carnitine from their diet or suffer from dietary deficiencies of this nutrient. As a result, they may develop heart disease, skeletal muscle weakness, or low blood sugar. If you experience these symptoms and are found to have carnitine deficiency, your health care provider may recommend use of the supplement levocarnitine, or L-carnitine.
…L-carnitine offers a variety of potential therapeutic uses, primarily related to the heart.
…Carnitine is available as a supplement in several forms. Only the L-carnitine forms are recommended. These include the following:
L-carnitine (LC), which is the most widely available, is the least expensive, and has been studied the most
L-acetylcarnitine (LAC), which appears to be best for Alzheimer’s disease and brain defects
L-propionylcarnitine (LPC), which may be best for angina and other heart problems
The D-carnitine form should not be used because it has produced undesirable side effects.
Recommended doses of L-carnitine vary depending on the health condition being treated. ….To improve fat metabolism and muscular performance: 1,000 mg to 2,000 mg usually divided into two doses.
…L-carnitine is not recommended for people with active liver or kidney disease. If you take L-carnitine as a supplement to improve fat metabolism and muscular performance, it is recommended that you skip using it one week each month.
According to Health Care Reality Check:
Carnitine supplementation with supraphysiological doses above and beyond that which the body requires, does not result in increased fat oxidation at rest or during exercise in well-nourished individuals; thus, it appears that we can synthesize the necessary amounts from a diet adequate in its precursors (lysine and methionine). Those medically diagnosed as carnitine-deficient may benefit from a supplement, but this condition is uncommon.
According to the National Organization for Rare Disorders:
Carnitine Deficiency Syndrome is a rare metabolic disorder that may be inherited in some cases, or occur as a result of other metabolic disorders
The average diet contains a small amount of carnitine. However, the body produces this amino acid naturally in the liver. The body cannot use more than it needs, so taking additional amounts of this supplement will have no impact on fat oxidation. If you are one of the few people that suffer from a rare carnitine deficiency, then you may benefit from supplementation. However, you will need a much higher dose than what is included in this pill. Furthermore, only certain forms of carnitine are used to treat this disorder, and you should see your physician if you think you may have this disorder and receive treatment.