L-Carnitine
L-carnitine is made in the body from the amino acids lysine and methionine, and is needed to release energy from fat. It transports fatty acids into mitochondria, the powerhouses of cells. In infancy, and in situations of high energy needs, such as pregnancy and breast-feeding, the need for L-carnitine can exceed production by the body. Therefore, L-carnitine is considered a "conditionally essential" nutrient.1
- Reliable and relatively consistent scientific data showing a substantial health benefit.
- Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
- For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
This supplement has been used in connection with the following health conditions:
| Used for | Amount | Why |
|---|---|---|
Angina | 1 gram two or three times per day |  [3 stars] Supplementing with L-carnitine may improve heart function and ease angina symptoms. |
Congestive Heart Failure | 500 mg two to three times per day with a doctor's supervision | [3 stars] Supplementing with L-carnitine can improve heart function and exercise capacity and reduce heart muscle damage due to insufficient oxygen. |
Heart Attack | 2 grams daily | [3 stars] Taking L-carnitine may help reduce damage and complications following a heart attack. |
Intermittent Claudication | 2 grams daily | as Propionyl-L-Carnitine[3 stars] In double-blind trials, supplementing with either L-carnitine or propionyl-L-carnitine (a form of L-carnitine) has increased walking distance in people with intermittent claudication. |
Obesity | 250 to 2,000 mg per day | [3 stars] The amino acid L-carnitine is thought to be potentially helpful for weight loss because of its role in fat metabolism. |
Attention Deficit–Hyperactivity Disorder | 100 mg per 2.2 lbs (1 kg) of body weight daily, up to a maximum of 4 grams per day |  [2 stars] In a double-blind study, supplementing with L-carnitine resulted in improvement in 54% of a group of boys with ADHD, compared with a 13% response rate in the placebo group. |
Autism | 50 mg per kilogram of body weight per day (half in the morning, half in the evening) | [2 stars] In a double-blind trial, supplementing with L-carnitine resulted in a modest improvement in disease severity in children with autism spectrum disorders.
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Chronic Fatigue Syndrome | 1 gram three times daily | [2 stars] L-carnitine is an important nutrient for energy production. Supplementation can make up for a possible deficiency. |
Chronic Obstructive Pulmonary Disease | 2 grams taken twice per day | [2 stars] Studies have shown that when L-carnitine is given to people with chronic lung disease, breathing during exercise improves. |
Erectile Dysfunction | 2 grams of each daily | as L-Carnitine and Acetyl-L-Carnitine[2 stars] In one study, supplementing with the combination of propionyl-L-carnitine (a form of L-carnitine) and acetyl-L-carnitine significantly improved erectile function in elderly men. |
High Cholesterol | 2 to 3 grams per day | [2 stars] L-carnitine has been found in some, but not all, clinical trials to reduce high cholesterol levels. |
High Triglycerides | 1 to 3 grams daily | [2 stars] Supplementing with L-carnitine may help normalize triglyceride levels. |
Intermittent Claudication | 2 grams a day of proprionyl-L-carnitine | [2 stars] In double-blind trials, supplementation with either L-carnitine or propionyl-L-carnitine (a form of L-carnitine) has increased walking distance in people with intermittent claudication. |
Male Infertility | 3 grams daily | [2 stars] L-carnitine appears to be necessary for normal functioning of sperm cells. Supplementing with it may improve sperm motility. |
Metabolic Syndrome | 2 to 3 grams daily | [2 stars] L-carnitine supplementation may reduce cardiovascular risk by improving metabolic parameters such as body weight, blood glucose control, insulin sensitivity, and lipid levels. |
Multiple Sclerosis and Drug-Induced Fatigue | 3 to 6 grams daily | [2 stars] Some drugs that are used to treat MS appear to deplete carnitine. In one trial, supplementing with L-carnitine significantly improved fatigue in 63% of drug-treated MS patients. |
Sickle Cell Anemia | 50 mg per 2.2 lbs (1 kg) of body weight daily | [2 stars] In a study of children with sickle cell anemia, supplementing with L-carnitine reduced the number of painful crises and improved abnormal heart function and pulmonary hypertension. |
Sprains and Strains and Exercise-Related Muscle Injury | 3 grams per day | [2 stars] One trial showed that people who take L-carnitine for three weeks before engaging in an exercise regimen are less likely to experience muscle soreness. |
Thalassemia | 50 to 100 mg per 2.2 lbs (1 kg) of body weight daily | [2 stars] Studies have shown that propionyl-L-carnitine (a form of L-carnitine) protects red blood cells of people with thalassemia against free radical damage. Supplementing with it may reduce the need for blood transfusions. |
Type 1 Diabetes | 1,500 to 2,000 mg daily | [2 stars] Supplementing with acetyl l-carnitine may reduce symptoms of diabetic neuropathy in people with type 1 diabetes. |
Type 2 Diabetes | 2 to 4 grams daily | [2 stars] Supplementing with L-carnitine may reduce glucose, cholesterol, and triglyceride levels, and support medical therapies for type 2 diabetes. |
Asthma | Refer to label instructions |  [1 star] In a double-blind trial, supplementing with L-carnitine improved lung function and overall asthma control, compared with a placebo, in children with asthma.
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Athletic Performance | Refer to label instructions | [1 star] L-carnitine has been popular as a potential aid in improving athletic performance because of its role in converting fat to energy. Some studies have found that it improves certain measures of muscle physiology. |
Cardiomyopathy | Refer to label instructions | [1 star] Inherited forms of cardiomyopathy seen in children may be responsive to L-carnitine. |
Liver Cirrhosis | Refer to label instructions | [1 star] L-carnitine injections have been used to improve circulation to the liver in people with cirrhosis. |
Mitral Valve Prolapse | Refer to label instructions | [1 star] In one report, deficient levels of L-carnitine were found in five people with MVP. One person was given L-carnitine and experienced a complete resolution of MVP symptoms. |
Raynaud’s Disease | Refer to label instructions | [1 star] In one study, people with Raynaud’s disease who were given L-carnitine showed less blood-vessel spasm in their fingers in response to cold exposure. |
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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.