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L-carnitine is a chemical that is made in the human brain, liver, and kidneys. It helps the body turn fat into energy.
L-carnitine is important for heart and brain function, muscle movement, and many other body processes. The body can convert L-carnitine to other chemicals called acetyl-L-carnitine and propionyl-L-carnitine. But it's not clear whether the benefits of these other carnitines are the same.
L-carnitine is used 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, serious kidney disease, and many other conditions, but there is no good scientific evidence to support these uses.
- L-carnitine deficiency. Oral and intravenous L-carnitine can treat primary and secondary L-carnitine deficiency.
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- Angina. Oral and intravenous L-carnitine may improve exercise tolerance and symptoms of angina during exercise in patients with angina.
Login for details - Congestive heart failure (CHF). Oral and intravenous L-carnitine may improve exercise capacity and symptoms of heart failure in patients with CHF.
Login for details - Hyperlipidemia. Oral or intravenous L-carnitine may slightly improve lipid levels in patients with hyperlipidemia. Oral, but not intravenous, L-carnitine may also improve lipoprotein(a) levels in patients with elevated lipoprotein(a).
Login for details - Kidney failure. Intravenous, but not oral, L-carnitine is FDA-approved for the prevention and treatment of L-carnitine deficiency in patients with kidney failure undergoing hemodialysis.
Login for details - Male infertility. Oral L-carnitine, taken alone or in combination with acetyl-L-carnitine, may increase sperm motility in males with infertility, leading to a greater likelihood of pregnancy in female partners.
Login for details - Myocarditis. Oral DL-carnitine may prevent myocarditis in children with diphtheria.
Login for details - Polycystic ovary syndrome (PCOS). Oral L-carnitine may improve ovulation and pregnancy rates in people with PCOS who are resistant to clomiphene and/or human chorionic gonadotropin (HCG). The effect of L-carnitine on body composition has also been investigated, with promising results.
Login for details - Valproic acid-induced toxicities. Oral and intravenous L-carnitine may improve neurologic and hepatic function and reduce ammonia levels in patients with these valproic acid-induced toxicities, but L-carnitine does not seem to reduce weight gain caused by valproic acid.
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- Acne. Topical L-carnitine has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Age-related fatigue. Small clinical studies suggest that oral L-carnitine may improve physical and mental fatigue associated with aging.
Login for details - Androgenic alopecia. It is unclear if topical L-carnitine is beneficial in people with androgenic alopecia.
Login for details - Anorexia nervosa. Login for details
- Athletic performance. Oral L-carnitine has been evaluated for its effect on athletic performance in several small and short-term clinical studies, with mixed results.
Login for details - Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral L-carnitine is beneficial in children with ADHD.
Login for details - Autism spectrum disorder. It is unclear if oral L-carnitine is beneficial in children with autism spectrum disorder.
Login for details - Arrhythmia. Small clinical studies suggest that oral L-carnitine may reduce the incidence of arrhythmias in patients with premature ventricular contractions.
Login for details - Beta-thalassemia. Small clinical studies suggest that oral L-carnitine may improve symptoms and reduce complications of beta-thalassemia minor, intermedia, and major.
Login for details - Cachexia. Small clinical studies suggest that oral L-carnitine may improve body composition and quality of life in patients with cancer-related cachexia.
Login for details - Cancer-related fatigue. It is unclear if oral L-carnitine is beneficial for improving fatigue in patients with advanced cancer.
Login for details - Celiac disease. It is unclear if oral L-carnitine is beneficial in patients with celiac disease.
Login for details - Chemotherapy-related fatigue. It is unclear if oral L-carnitine is beneficial in patients with fatigue due to sunitinib therapy.
Login for details - Chronic fatigue syndrome (CFS). It is unclear if oral L-carnitine is beneficial in patients with CFS.
Login for details - Chronic obstructive pulmonary disease (COPD). It is unclear if oral L-carnitine is beneficial in patients with COPD.
Login for details - Cirrhosis. It is unclear if oral L-carnitine is beneficial in patients with cirrhosis.
Login for details - Cognitive function. It is unclear if oral L-carnitine is beneficial for improving cognitive function in healthy individuals.
Login for details - Coronary heart disease (CHD). It is unclear if oral L-carnitine is beneficial in patients with CHD.
Login for details - Diabetes. Oral L-carnitine may improve glycemic control in patients with diabetes, but it is unclear if these improvements are clinically meaningful. It is also unclear if L-carnitine can improve lipid profiles or weight loss in these patients.
Login for details - Dilated cardiomyopathy. Small clinical studies suggest that oral L-carnitine may improve ejection fraction in children with dilated cardiomyopathy and adults with ischemic cardiomyopathy.
Login for details - Dry eye. Topical L-carnitine has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Endometriosis. Login for details
- Exercise-induced muscle soreness. Small clinical studies suggest that oral L-carnitine may slightly reduce exercise-induced muscle soreness.
Login for details - Hepatic encephalopathy. Oral or intravenous L-carnitine may improve biochemical markers of disease severity in patients with hepatic encephalopathy, but L-carnitine does not seem to improve patient-oriented outcomes such as fatigue or quality of life.
Login for details - Hepatitis-related fatigue. It is unclear if oral L-carnitine is beneficial in patients with hepatitis-related fatigue.
Login for details - Hepatitis B. Oral L-carnitine has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Hepatitis C. Small clinical studies suggest that oral L-carnitine may improve response to treatment and markers of liver function in patients with hepatitis C.
Login for details - HIV/AIDS. Login for details
- Hyperthyroidism. It is unclear if oral L-carnitine is beneficial in patients with hyperthyroidism.
Login for details - Hypertriglyceridemia. It is unclear if oral L-carnitine is beneficial in patients with hypertriglyceridemia.
Login for details - Hypothyroidism. It is unclear if oral L-carnitine is beneficial for improving fatigue in patients with hypothyroidism.
Login for details - Infertility. It is unclear if oral L-carnitine is beneficial for female infertility.
Login for details - Intermittent claudication. Login for details
- Liver disease. Small clinical studies suggest that oral L-carnitine may modestly improve some, but not all, lipid parameters in adults with liver disease.
Login for details - Liver transplant. It is unclear if oral L-carnitine is beneficial in patients awaiting a liver transplant.
Login for details - Low birth weight. It is unclear if oral or intravenous L-carnitine is effective for increasing body weight in preterm infants. Several small clinical studies show conflicting results.
Login for details - Lyme disease. Login for details
- Metabolic syndrome. It is unclear if oral or intravenous L-carnitine is beneficial in patients with metabolic syndrome.
Login for details - Migraine headache. It is unclear if oral L-carnitine is beneficial in patients with migraine headaches.
Login for details - Muscle cramps. It is unclear if oral L-carnitine is beneficial in patients with muscle cramps.
Login for details - Multiple sclerosis-related fatigue. It is unclear if oral L-carnitine is beneficial in patients with multiple sclerosis-related fatigue.
Login for details - Myocardial infarction (MI). It is unclear if oral or intravenous L-carnitine is beneficial in patients who have experienced an MI.
Login for details - Narcolepsy. It is unclear if oral L-carnitine is beneficial in patients with narcolepsy.
Login for details - Neonatal apnea. It is unclear if intravenous L-carnitine is beneficial for preventing neonatal apnea in premature infants.
Login for details - Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral L-carnitine is beneficial in patients with NAFLD.
Login for details - Nonalcoholic steatohepatitis (NASH). It is unclear if oral L-carnitine is beneficial in patients with NASH.
Login for details - Obesity. Oral L-carnitine seems to have a small effect on weight loss in overweight or obese individuals when taken for up to 6 months, but some conflicting results exist. Doses of 2 grams daily seem to offer the most benefit.
Login for details - Peripheral arterial disease (PAD). It is unclear if oral L-carnitine is beneficial in patients with PAD.
Login for details - Rett syndrome. It is unclear if oral L-carnitine is beneficial in patients with Rett syndrome.
Login for details - Sarcopenia. Oral L-carnitine may be beneficial for preventing sarcopenia in adults over 75 years of age, but not in healthy older females.
Login for details - Sepsis. Small clinical studies suggest that intravenous L-carnitine may not reduce mortality in patients with sepsis, although patients with more severe sepsis may see some benefit.
Login for details - Spinal muscular atrophy. Login for details
- Theophylline-induced cardiac toxicity. It is unclear if intravenous L-carnitine is beneficial in patients with theophylline-induced cardiac toxicity.
Login for details - Toxin-induced liver damage. Small clinical studies have evaluated oral and intravenous L-carnitine for the management of liver damage caused by different classes of drugs, including antimycobacterial antibiotics and asparaginase-based agents, with promising results.
Login for details - Urinary tract infections (UTIs). It is unclear if oral L-carnitine is beneficial in children with UTIs.
Login for details - Venous leg ulcers. Login for details
When taken by mouth: L-carnitine is likely safe when taken for up to 12 months. It can cause side effects such as stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a "fishy" odor. Avoid using D-carnitine and DL-carnitine. These forms of carnitine might block the effects of L-carnitine and cause symptoms that resemble L-carnitine deficiency.
Special Precautions & Warnings:
Pregnancy: There isn't enough reliable information to know if L-carnitine is safe to use when pregnant. Stay on the safe side and avoid use.Breast-feeding: Taking L-carnitine is possibly safe when taken by mouth while breast-feeding in the amounts recommended by a healthcare provider. 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 are unknown.
Children: L-carnitine is possibly safe when used appropriately by mouth, short-term. It has been used safely by mouth for up to 6 months.
Underactive thyroid (hypothyroidism): Taking L-carnitine might make symptoms of hypothyroidism worse.
Seizures: L-carnitine seems to make seizures more likely in people who have had seizures before. If you have had a seizure, don't take L-carnitine.
Acenocoumarol (Sintrom)
Interaction Rating=Moderate Be cautious with this combination.
Acenocoumarol (Sintrom) is used to slow blood clotting. L-carnitine might increase the effectiveness of acenocoumarol (Sintrom). Increasing the effectiveness of acenocoumarol (Sintrom) might slow blood clotting too much. The dose of your acenocoumarol (Sintrom) might need to be changed.
Thyroid hormone
Interaction Rating=Moderate Be cautious with this combination.
L-carnitine seems to decrease how well thyroid hormone works in the body. Taking L-carnitine with thyroid hormone might decrease the effectiveness of the thyroid hormone.
Warfarin (Coumadin)
Interaction Rating=Moderate Be cautious with this combination.
Warfarin (Coumadin) is used to slow blood clotting. L-carnitine might increase the effects of warfarin (Coumadin) and increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
D-carnitine: D-carnitine might interfere with the way the body uses L-carnitine. Taking D-carnitine might cause L-carnitine levels to drop too low (L-carnitine deficiency). Don't take D-carnitine with L-carnitine.
There are no known interactions with foods.
L-carnitine has most often been used by adults in doses of 2 grams by mouth daily. In children, L-carnitine has most often been used in doses of 50-100 mg/kg by mouth daily, for up to one year. Speak with a healthcare provider to find out what dose might be best for a specific condition.
3-carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium inner salt, (3-carboxy2-hydroxypropyl) trimethylammonium hydroxide inner salt, 3-hydroxy-4-N-trimethylaminobutyrate, Aminocarnitine, B-hydroxy-N-trimethyl aminobutyric acid, Beta-hydroxy-gamma-trimethylammonium butyrate, Beta-hydroxyl-gamma-tributyl aminobutyrate, B(t) Factor, Carnitine, Carnitor, D-Carnitine, DL-Carnitine, Facteur B(t), L-3-hydroxy-4-(trimethylammonium)-butyrate, Levocarnitine, Lévocarnitine, Levocarnitine Fumurate, L-b-hydroxy-c-N-trimethylaminobutyric acid, 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).
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