What is L- carnitine
L-carnitine is a chemical similar to an amino acid that is produced in the body. L-carnitine helps the body turn fat into energy. The body can convert L-carnitine to other chemicals called acetyl-L-carnitine and propionyl-L-carnitine. But, no one knows whether the benefits of these other carnitines are the same. Until more is known, don’t switch one form of carnitine for another.
L-carnitine is taken by mouth to increase L-carnitine levels in people whose natural level of L-carnitine is too low. Some people also use L-carnitine for conditions of the heart and blood vessels, overactive thyroid, inability to become pregnant within a year of trying to conceive (infertility), serious kidney disease, and many other conditions, but there is no good scientific evidence to support these uses.
- 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 or intravenously (by IV) 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 with cardiac syndrome X. People with this condition have chest pain but not blocked arteries.
- Heart failure and fluid build up in the body (congestive heart failure or CHF). Taking L-carnitine by mouth or intravenously (by IV) seems to improve symptoms and increase exercise ability in people with heart failure. Taking a specific product containing L-carnitine and coenzyme Q10 also appears to improve symptoms of heart failure.
- Serious kidney disease (end-stage renal disease or ESRD). People in the last stage of long-term, serious kidney disease need to undergo hemodialysis, which can lower L-carnitine levels. The US Food and Drug Administration (FDA) has approved giving L-carnitine intravenously (by IV) but not by mouth to treat and prevent L-carnitine deficiency in these patients. There is mixed evidence about the effects of L-carnitine in treating disorders caused by low carnitine levels in people with serious kidney disease undergoing hemodialysis. Taking L-carnitine by mouth or giving L-carnitine intravenously might improve markers of anemia and inflammation in people with this condition. But L-carnitine does not seem to improve quality of life, muscle cramping, low blood pressure, breathing function, or exercise performance.
- Overactive thyroid (hyperthyroidism). Taking L-carnitine seems to improve symptoms such as rapid or pounding heartbeat, nervousness, and weakness in people with high thyroid hormone levels.
- Conditions in a man that prevent him from getting a woman pregnant within a year of trying to conceive (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. Some research shows that this increases the chance of pregnancy.
- Swelling (inflammation) of the heart (myocarditis). Taking D,L-carnitine by mouth seems to reduce the risk of death from myocarditis.
- A hormonal disorder that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). Clomiphene is a medication used to help with ovulation. However, it doesn’t work well in some women with PCOS. In these women, taking L-carnitine increases ovulation and the chance of getting pregnant. Also, taking L-carnitine might help with weight loss and improve blood sugar levels in these women.
- Toxic side effects caused by the drug valproic acid. Toxicity caused by valproic acid seems to be linked with L-carnitine deficiency. Giving L-carnitine intravenously (by IV) can prevent severe liver toxicity in people who accidentally ingested or took too much valproic acid.