July 28, 2016

L-Carnitine

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What other names is L-carnitine known by?

3-carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium inner salt, (3-carboxy2-hydroxypropyl) trimethylammonium hydroxide inner salt, 3-hydroxy-4-N-trimethylaminobutyrate, B-hydroxy-N-trimethyl aminobutyric acid, Beta-hydroxy-gamma-trimethylammonium butyrate, B(t) Factor, Carnitine, Carnitor, D-Carnitine, DL-Carnitine, Facteur B(t), L-3-hydroxy-4-(trimethylammonium)-butyrate, Levocarnitine, Lévocarnitine, Levocarnitine Fumurate, L-Carnitina, L-Carnitine Fumarate, L-Carnitine L-Tartrate, L-Carnitine Tartrate, (R)-(3-carboxy-2-hydroxypropyl) trimethylammonium hydroxide, (R)-3-hydroxy-4-trimethylammonio-butyrate, Vitacarn, Vitamin B(t), Vitamine B(t).

What is L-carnitine?

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.

Effective for...

  • Serious kidney disease. Most research suggests that taking L-carnitine by mouth or intravenously (by IV) can improve red blood cell counts during hemodialysis. The US Food and Drug Administration (FDA) has approved L-carnitine for the treatment and prevention of L-carnitine deficiency in people with serious kidney disease who are undergoing hemodialysis.
  • L-carnitine deficiency. The FDA has approved L-carnitine for treating L-carnitine deficiency caused by certain genetic diseases.

Possibly Effective for...

  • Chest pain (angina). Taking L-carnitine by mouth seems to improve exercise tolerance in people with chest pain. Taking L-carnitine along with standard treatment also seems to reduce chest pain and improve exercise ability in people who have chest pain but not blocked arteries.
  • Heart failure. Taking L-carnitine by mouth seems to improve symptoms and increase exercise ability in people with heart failure. Taking a specific product containing L-carnitine and coenzyme Q-10 (Carni Q-Gel) also appears to improve symptoms of heart failure.
  • High thyroid hormone levels (hyperthyroidism). Taking L-carnitine seems to improve symptoms such as rapid or pounding heartbeat, nervousness, and weakness in people with high thyroid hormone levels.
  • Male infertility. Most research shows that taking L-carnitine, alone or in combination with acetyl-L-carnitine, increases sperm count and sperm movement in men with fertility problems.
  • Inflammation of the heart (myocarditis). Taking L-carnitine by mouth seems to reduce the risk of death from myocarditis.
  • Preventing side effects caused by valproic acid (Depacon, Depakene, Depakote, VPA), a seizure medication. Using L-carnitine intravenously (by IV) can prevent the side effects of valproic acid.

Insufficient Evidence to Rate Effectiveness for...

  • Age-related fatigue. Taking L-carnitine might improve physical and mental fatigue, increase muscle mass, and decrease fat mass in elderly people.
  • Hair loss (androgenic alopecia). Early research suggests that applying an L-carnitine solution twice daily for 6 months increases hair on the scalp.
  • Athletic performance. Intense exercise has been linked to a decrease in L-carnitine blood levels. However, research on the use of L-carnitine for improving athletic performance is inconsistent. Some studies suggest that L-carnitine improves athletic performance and endurance. However, other research suggests L-carnitine provides no benefits.
  • Attention deficit-hyperactivity disorder (ADHD). Taking L-carnitine does not appear to reduce ADHD symptoms in most children.
  • Autism. Early research suggests that taking L-carnitine by mouth daily for 3 months reduces the severity of autism in children according to some but not all scales.
  • Irregular heartbeat (arrhythmia). Early research suggests that L-carnitine might reduce irregular heartbeat.
  • Blood disorder called beta-thalassemia. Early research suggests that L-carnitine might reduce symptoms of a blood disorder called beta-thalassemia.
  • Wasting syndrome (cachexia). Early research suggests that taking L-carnitine can increase body mass index (BMI) and improve lean body mass in people with cancer and wasting syndrome.
  • Weakening heart muscle (cardiomyopathy). Early research suggests that L-carnitine improves heart function in adults or children with a weak heart muscle.
  • Cancer-related fatigue. Some cancer patients have low blood levels of L-carnitine. Some early research suggests that taking L-carnitine might improve fatigue in advanced cancer patients. However, other research suggests that it has no benefit.
  • Celiac disease-related fatigue. Some research shows that taking L-carnitine seems to help fatigue associated with celiac disease. However, L-carnitine does not seem to improve depression or quality of life.
  • Chronic fatigue syndrome. Early research suggests that taking L-carnitine for 2 months can improve symptoms of fatigue.
  • Lung disease (chronic obstructive pulmonary disease). Early research suggests that L-carnitine can improve exercise performance in people with chronic obstructive pulmonary disease (COPD).
  • Clogged arteries (coronary artery disease). Early research suggests that taking L-carnitine before exercise does not improve endurance in people with clogged arteries.
  • Diabetes. Some research suggests that L-carnitine might improve blood sugar control, but most research shows that L-carnitine does not improve blood sugar in people with diabetes. However, L-carnitine might improve glycemic control when taken along with certain diabetes medications.
  • Fatigue. Early research shows that taking L-carnitine daily for 8 days does not reduce fatigue in healthy people.
  • Fragile-X syndrome. Some research suggests that L-carnitine reduces hyperactive behavior in children with fragile-X syndrome.
  • Declining brain function related to liver disease. Early research shows that taking L-carnitine daily for 60-90 days reduces ammonia levels and improves brain function in people with declining brain function related to severe liver disease.
  • Fatigue due to hepatitis. Early research shows that taking L-carnitine daily reduces fatigue in people with hepatitis C who are also being treated with medication.
  • Hepatitis C. Taking L-carnitine with the medications interferon-alpha and ribavirin seems to improve the response to treatment in people with hepatitis C.
  • High lipid (fat) levels in the blood. Early research shows that taking L-carnitine daily can reduce total cholesterol, low-density lipoprotein (LDL or "bad") cholesterol, and triglycerides in children with high lipid levels. Also, taking L-carnitine can reduce levels of lipoprotein(a), a possible risk factor for cardiovascular disease, in people with high levels of lipoprotein(a).
  • High triglycerides. Early research suggests that L-carnitine does not reduce triglyceride levels in people with high triglyceride levels.
  • Low birth weight. Some research suggests that giving premature infants L-carnitine by mouth or intravenously (by IV) can increase weight. However, other research suggests that it does not increase body weight in premature infants.
  • Memory. Early research shows that taking L-carnitine daily for 3 days does not improve memory in young adult females.
  • Migraine headache. Early research suggests that taking L-carnitine daily, with or without magnesium oxide for 12 weeks, does not reduce migraines.
  • Multiple sclerosis-related fatigue. Some people with multiple sclerosis have low blood levels of L-carnitine. Early research shows that taking L-carnitine daily decreases some aspects of fatigue in people with multiple sclerosis who also have low L-carnitine levels.
  • Heart attack. There is inconsistent evidence about the effects of using of L-carnitine after a heart attack. Some research suggests that taking L-carnitine by mouth after a heart attack improves heart function and reduces the risk of death. However, other studies suggest that it provides no benefit.
  • Breathing problems while sleeping in infants. Early research suggests that adding L-carnitine to intravenous (IV) nutrition does not reduce breathing problems while sleeping in infants.
  • Nonalcoholic liver disease (nonalcoholic steatohepatitis, NASH). Early research suggests that L-carnitine improves some aspects of liver function in people with liver disease not related to drinking alcohol.
  • Blocked blood vessels not in the heart or brain. Some early research suggests that L-carnitine might improve walking in people with blocked blood vessels not in the heart or brain. However, other research suggests that it does not provide any benefits.
  • A rare inherited disorder that affects the nervous system (Rett syndrome). Taking L-carnitine might improve well-being and movement in girls with Rett syndrome.
  • Weight loss. Taking L-carnitine by itself does not appear to reduce body weight in overweight or obese people. However, other research suggests that taking L-carnitine with certain other medications or supplements appears to reduce body weight and body mass index.
  • Eating disorders.
  • Leg ulcers.
  • Lyme disease.
  • Other conditions.
More evidence is needed to rate L-carnitine for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).


Therapeutic Research Faculty copyright

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