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L-Carnitine

a nutraceutical product - treats Infertility, Arrhythmia, Exercise performance, Alzheimer's disease,... more

Generic Name: levocarnitine  |  Brand Name: Carnitor

Brand Names: L-Carnitine, Levocarnitine Novaplus, Carnitor

Category

Herbs & Supplements

Synonyms

AcCn, acetyl-L-carnitine, B (t) Factor, β-hydroxy-gamma-N-trimethylamino butyrate, carnitene, carnitine, carnitor, canitor, D-carnitine, D,L-carnitine, LAC, L-acetyl-carnitine, LCLT, L-carnitina, L-carnitine L-tartrate, L-CARNIPURE, levacecarnine, levocarnitine, levocarnitine chloride, LK-80, L-propionylcarnitine, propionil-L-carnitine, propionyl-L-carnitine, total parenteral nutrition, TPN, VitaCarn®, vitamin B(t), vitamin Bt.

Background

The main function of L-carnitine is to transfer long-chain fatty acids in the form of their acyl-carnitine esters across the inner mitochondrial membrane before beta-oxidation. In humans, it is synthesized in the liver, kidney, and brain and actively transported to other areas of the body. For example, 98% of the total body L-carnitine is confined to the skeletal and cardiac muscle at concentrations approximately 70 times higher than in the blood serum.

Supplementation may be necessary in rare cases of primary carnitine deficiency, which may be caused by a defect in carnitine biosynthesis, a defect in carnitine active transport into tissue, or a defect in renal (kidney) conservation of carnitine. Known conditions of secondary deficiency of carnitine (insufficiency), in which L-carnitine is effective, include chronic stable angina and intermittent claudication characterized by distinct tissue hypoxia (low oxygen levels). Another condition that may benefit from carnitine supplementation is decreased sperm motility.

Although use in preterm infants suggests carnitine supplementation may aid in maintaining or increasing plasma carnitine levels and possibly weight gain, carnitine is not routinely added to preterm total parenteral nutrition (TPN). However, soy-based infant formulas are fortified with carnitine to levels found in breast milk.

In 1986, the U.S. Food and Drug Administration (FDA) approved L-carnitine for use in primary carnitine deficiency. D-carnitine or DL-carnitine may cause secondary L-carnitine deficiency and should not be used.

Evidence

DISCLAIMER: These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Nutritional deficiencies (primary and secondary carnitine deficiency in adults): Carnitine supplementation, both intravenous (injection) and oral (by mouth), is indicated for cases of primary and secondary carnitine deficiency. Use of L-carnitine in primary carnitine deficiency restores plasma carnitine levels to nearly normal levels. Muscle carnitine levels may rise only slightly; however muscle function can be normalized.
Grade: A

Angina (chronic stable): Evidence from clinical trials suggests that L-carnitine and L-propionyl-carnitine (propionyl-L-carnitine) are effective in reducing symptoms of angina. Carnitine may not offer further benefit when patients continue conventional therapies. Additional study is needed to confirm these findings.
Grade: B

Attention-deficit hyperactivity disorder (ADHD): Only one study has examined the effects of L-carnitine in boys with ADHD. Although results were promising, additional study is needed before a strong recommendation can be made.
Grade: C

AIDS: Carnitine may be beneficial in AIDS treatment by increasing proliferation of mononuclear cells and increasing CD4 counts. Additional study is needed to make a firm recommendation.
Grade: C

Alcoholism: L-carnitine or acetyl-L-carnitine may be of benefit to alcoholics. Additional study is needed to make a firm recommendation.
Grade: C

Alzheimer's disease: Early evidence suggests the effectiveness of L-carnitine and/or acetyl-L-carnitine for Alzheimer's disease. However, the evidence is mixed.
Grade: C

Arrhythmia (abnormal heart rhythms): Although preliminary results are promising, there is insufficient available evidence to recommend for or against this use.
Grade: C

Cerebral ischemia (lack of adequate blood flow to the brain): There are a limited number of studies showing a positive effect of L-acetyl-carnitine on cerebral blood flow and metabolism of the brain in patients who have suffered from stroke. Additional study is required before a firm recommendation can be made.
Grade: C

Congestive heart failure: Although preliminary results are promising, there is insufficient available evidence to recommend for or against the use of carnitine for congestive heart failure.
Grade: C

Dementia (elderly): Most of the studies related to dementia suffer from various weaknesses. Although preliminary evidence is promising, there is insufficient available evidence to recommend for or against this use.
Grade: C

Depression: Although preliminary evidence is promising, there is insufficient available evidence to recommend for or against the use of carnitine in the treatment of depression.
Grade: C

Diabetes mellitus: It has been suggested that L-carnitine under constant infusion is able to increase insulin sensitivity in patients with diabetes mellitus type II and enhance glucose oxidation. Carnitine may also decrease fasting blood glucose and Lp(a). Additional study is needed before a firm recommendation can be made.
Grade: C

Diabetic neuropathy: Early evidence suggests that acetyl-L-carnitine may be beneficial for individuals with diabetic neuropathy. Additional study is needed before a firm recommendation can be made.
Grade: C

Dialysis (CAPD): L-carnitine taken by mouth has been used in patients receiving continuous ambulatory peritoneal dialysis (CAPD), but does not appear to lead to the resolution of hypertriglyceridemia. Additional study is needed before a firm recommendation can be made.
Grade: C

Dialysis (hemodialysis): Although preliminary evidence is promising, there is insufficient available evidence to recommend for or against the use of carnitine for hemodialysis patients.
Grade: C

Diphtheria (throat disease): Early studies suggest that carnitine may be beneficial for patients with diphtheria, mainly in terms of myocardial (heart) damage. However, additional study is needed to confirm these findings.
Grade: C

Erectile dysfunction: Preliminary studies suggest that propionyl-L-carnitine, with acetyl-L-carnitine or sildenafil may be beneficial for patients with erectile dysfunction. However, more rigorous trials should be performed in order to recommend carnitine for routine use in erectile dysfunction.
Grade: C

Exercise performance: Overall, the data is mixed in terms of the benefits of L-carnitine for exercise performance. Until confirmed, a strong recommendation for L-carnitine cannot be made for increased exercise endurance.
Grade: C

Fatigue: There are several promising reports on the use of L-carnitine for fatigue. However, additional study is warranted in this area.
Grade: C

Fragile X syndrome: There is insufficient evidence to support the use of carnitine in the treatment of hyperactive behavior of fragile -X children.
Grade: C

Hepatic encephalopathy (brain disease): Preliminary evidence suggests L-carnitine may be of benefit to individuals with hepatic encephalopathy, in terms of ammonia levels and psychometric functioning. Additional study is needed to make a firm recommendation.
Grade: C

Huntington's chorea/disease: One preliminary study showed that L-acetyl-carnitine possesses neither efficacy nor toxicity in patients with Huntington's disease. Further trials are required before a firm recommendation can be made.
Grade: C

Hyperlipoproteinemia (high levels of lipoprotein and cholesterol in the blood): Although preliminary evidence is promising, there is insufficient available evidence to recommend for or against the use of carnitine for hyperlipoproteinemia.
Grade: C

Hyperthyroidism: Although preliminary evidence is promising, there is insufficient available evidence to recommend for or against the use of carnitine for hyperthyroidism.
Grade: C

Infertility (asthenospermia): Early evidence shows a positive effect for carnitine and/or acetyl-L-carnitine in terms of increased sperm motility. However, additional study is needed before a firm conclusion can be made.
Grade: C

Lactic acidosis: Although early evidence appears promising, currently there is insufficient evidence to recommend carnitine in the treatment of lactic acidosis.
Grade: C

Liver disease (cirrhosis): Although early evidence appears promising, currently there is insufficient evidence to recommend carnitine in the treatment of liver cirrhosis.
Grade: C

Memory: There are a limited number of studies relevant to the use of carnitine for memory. Carnitine does not appear to have any effect on memory. Additional study is needed before a firm recommendation can be made.
Grade: C

Myocardial infarction (heart attack): Currently there is insufficient evidence to support the use of carnitine for myocardial infarction. Additional study is needed in this area.
Grade: C

Nutritional deficiencies (adults): Currently there is insufficient evidence to support the use of carnitine in the total parenteral nutrition for adults. Additional study is needed in this area.
Grade: C

Nutritional deficiencies (full term infants): Despite a large number of studies, it is not clear what effect, if any, the addition of carnitine has on weight gain in full term infants. Additional study is needed.
Grade: C

Nutritional deficiencies (premature infants): Despite a large number of studies, it is not clear what effect, if any, the addition of carnitine has on weight gain in premature infants. Additional study is needed.
Grade: C

Obesity: Early evidence shows that L-carnitine may have no effect on weight loss in obese patients. Further studies are needed before a firm recommendation can be made.
Grade: C

Peripheral neuropathy (nerve damage): Currently there is insufficient evidence to support the use of carnitine for peripheral neuropathy.
Grade: C

Peripheral vascular disease: Propionyl-L-carnitine and L-carnitine may treat peripheral vascular disease, especially in patients with severe limitations in peripheral circulation. The comparative effectiveness of propionyl-L-carnitine and other recognized treatments is unclear. More study is needed to make a firm recommendation.
Grade: C

Peyronie's disease: Although early evidence is promising, more study is needed before a firm recommendation can be made.
Grade: C

Pregnancy (miscarriage): Currently there is insufficient evidence to support the use of carnitine for miscarriage.
Grade: C

Respiratory distress (adults): Currently there is insufficient evidence to support the use of carnitine for respiratory distress in adults.
Grade: C

Respiratory distress (infants): Currently there is insufficient evidence to support the use of carnitine for respiratory distress in infants.
Grade: C

Rett's syndrome: There are promising results on the use of carnitine for this condition. Before a strong recommendation can be made, additional well-designed trials are needed.
Grade: C

Sickle cell disease: Preliminary evidence suggests the absence of any therapeutic effect of propionyl-L-carnitine for sickle cell disease. Additional studies are required before a firm recommendation can be made.
Grade: C

Surgerical uses (bypass): The results of studies on the use of carnitine in improving the functioning of myocardium (heart muscle) during open-heart surgery are controversial. Currently, there is insufficient available evidence to recommend for or against the use of carnitine.
Grade: C

Tuberculosis: A preliminary study suggests antibacterial activity may be increased in patients with tuberculosis given acetyl-L-carnitine. Additional study is needed to confirm these findings.
Grade: C

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