What is L-Carnitine?

7/7/2017  |  Supplement Ingredients

L-carnitine is an amino acid (a building block for proteins) that is naturally produced in the body.

L-carnitine supplements are used to increase L-carnitine levels in people whose natural level of L-carnitine is too low because they have a genetic disorder, are taking certain drugs (valproic acid for seizures), or because they are undergoing a medical procedure (hemodialysis for kidney disease) that uses up the body's L-carnitine. It is also used as a replacement supplement in strict vegetarians, dieters, and low-weight or premature infants.

L-carnitine is used for conditions of the heart and blood vessels including heart-related chest pain, congestive heart failure (CHF), heart complications of a disease called diphtheria, heart attack, leg pain caused by circulation problems (intermittent claudication), and high cholesterol.

Some people use L-carnitine for muscle disorders associated with certain AIDS medications, difficulty fathering a child (male infertility), a brain development disorder called Rett syndrome, anorexia, chronic fatigue syndrome, diabetes, overactive thyroid, attention deficit-hyperactivity disorder (ADHD), leg ulcers, Lyme disease, and to improve athletic performance and endurance.

The body can convert L-carnitine to other amino acids called acetyl-L-carnitine and propionyl-L-carnitine. But, no one knows whether the benefits of carnitines are interchangeable. Until more is known, don't substitute one form of carnitine for another.

How does it work?

L-carnitine helps the body produce energy. It is important for heart and brain function, muscle movement, and many other body processes.


Uses / Benefits: 

Cardiovascular 
Congestive heart failure, irregular heart rhythms and peripheral vascular disease (poor circulation to the arms or legs) are all common consequences of cardiovascular disease. L-carnitine has been shown to support the cardiovascular system, even in the face of these consequences. 70% of the metabolic energy required by the heart is supplied by fatty acids. No other organ in the body has higher concentrations of L-carnitine.

Sports and muscle metabolism 
During strenuous physical exercise, the body requires large amounts of glucose and fatty acids to produce energy. L-carnitine has been shown to reduce the respiratory quotient (RQ) in athletes. A lower RQ reflects more fatty acid burning and less glucose utilization. This glucose-sparing effect helps delay the onset of exhaustion and enhances performance. Improved performance has been confirmed by the improved VO2 Max (a measure of maximal aerobic capacity) of athletes using L-carnitine.

Dr. William Kraemer, from the Ball State Human Performance Laboratory, presented the results of a study on muscle soreness in "weekend warrior" athletes. It showed that L-carnitine tartrate, prior to high intensity exercise, is effective in assisting muscle recovery and reducing muscle soreness following exercise.

Fat metabolism and weight loss 
Because of its vital role in fat metabolism, another obvious benefit of L-carnitine supplementation is in weight loss. Numerous animal and human studies have shown L-carnitine to promote muscle deposition instead of fat.

Brain health 
Because of its unique chemical properties, acetyl L-carnitine (ALC) is able to cross into the brain easily, providing neuroprotective benefits. Besides aiding in fat metabolism, ALC directly stimulates the production of acetylcholine, a powerful neurotransmitter. Many current studies of L-carnitine and age-related changes in memory or mood have shown L-carnitine to benefit or delay those changes.

Sperm motility 
Infertility research has shown approximately 30% of cases to be directly related to the man alone, and not the woman. One Italian study showed that 78% of men had improvement in sperm counts and motility with 3 grams of L-carnitine daily.


Side Effects:


L-carnitine is LIKELY SAFE for most people when taken by mouth and when used as an injection, with the approval of a healthcare provider. It can cause side effects such as nausea, vomiting, stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a "fishy" odor.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There is not enough reliable information about the safety of using L-carnitine if you are pregnant. Stay on the safe side and avoid use.

Taking L-carnitine is POSSIBLY SAFEin breast-feeding women when taken by mouth in the amounts recommended. Small amounts of L-carnitine have been given to infants in breast milk and formula with no reported side effects. The effects of large amounts taken by a breast-feeding mother are unknown.

Children: L-carnitine is POSSIBLY SAFE when used appropriately by mouth or intravenously (by IV), short-term.

Under-active thyroid (hypothyroidism): Taking L-carnitine might make symptoms of hypothyroidism worse.

Kidney failure: Using DL-carnitine has been reported to cause symptoms such as muscle weakness and eye drooping when administered intravenously (by IV) after dialysis. L-carnitine does not seem have this effect.

Seizures: L-carnitine seems to make seizures more likely in people who have had seizures before. If you have had a seizure, do not use L-carnitine.

References / Sources: 
http://www.webmd.com/vitamins-supplements/ingredientmono-1026-l-carnitine.aspx?activeingredientid=1026
https://www.nutritionexpress.com/showarticle.aspx?articleid=89

Submit Comment

  • (will not be displayed)

* Required Fields

« Back
© Developed by CommerceLab