L-Carnitine

Insufficient Evidence 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 the 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 the 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 the 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.
• A 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 fatigues. 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 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.