L-carnitine: Benefits, Supplements and Sources
L-carnitine is an amino acid made by the body and found in some supplements. L-carnitine has many health benefits including heart health, brain health and potentially weight loss.
What is L-carnitine?
L-carnitine is an amino acid made by the body and found in some food and supplements. L-carnitine is found in almost every cell of the body. It plays a critical role in energy production by turning fat into energy.
About 95% of L-carnitine is stored in the muscles with trace amounts in the blood, liver, heart and kidneys. Most people obtain small amounts of L-carnitine from eating animal products like meat and dairy.
What are the benefits of L-carnitine?
Below are potential health advantages of L-carnitine.
- Heart Health: L-carnitine may contribute to the management of certain heart conditions. Some studies suggest it can reduce the risk of arrhythmia and angina (chest pain), although its effectiveness in preventing heart failure or heart attacks remains uncertain.
- Peripheral Artery Disease: Research indicates that L-carnitine may alleviate leg pain and improve walking distance for individuals suffering from intermittent claudication, a symptom of peripheral artery disease.
- Male Infertility: L-carnitine might enhance sperm quality and motility in some men facing infertility, although it does not appear to increase pregnancy rates.
- Diabetic Neuropathy: Preliminary studies suggest that acetyl-L-carnitine might help lessen nerve pain and improve nerve function in individuals with diabetic neuropathy.
- Alzheimer's Disease and Cognitive Function: Some research indicates that acetyl-L-carnitine may positively affect cognitive function and potentially slow the progression of Alzheimer’s disease, but further investigation is necessary.
- Weight Loss (Indirectly): L-carnitine might assist in weight loss by promoting fat oxidation and potentially increasing energy expenditure. However, its overall effect on weight loss is likely to be modest and more pronounced when combined with a healthy diet and regular exercise.
- Depression: There is some research that shows that L-carnitine can reduce symptoms of depression.
- Exercise performance: L-carnitine is frequently marketed as a supplement for enhancing athletic performance, but research on this specific topic shows mixed results.
Foods rich in L-carnitine
L-carnitine is found in animal products, especially red meat. It can also be found in poultry, fish and dairy foods. Below is a list of foods rich in L-carnitine.
- Beef steak
- Ground beef
- Milk (cow’s milk)
- Codfish
- Chicken breast
- Ice cream
- Cheese (cheddar and hard cheeses)
L-carnitine supplements
It is best to consume L-carnitine from your diet, but if you are unable to consume the necessary L-carnitine levels you may need to consider a supplement. Vegetarians and vegans tend to have lower L-carnitine levels and may want to consider supplementation.
Research shows various dosage recommendations for L-carnitine supplements:
- Acetyl-L-carnitine: This form is best for brain health and function. Doses vary from 500 to 3,000 mg per day.
- L-carnitine L-tartrate: This form is most effective for exercise performance. Doses vary from 1,000 to 4,500 mg per day.
- Propionyl-L-carnitine: This form may help improve blood flow in those with high blood pressure or related health conditions. A 2005 study used a dose of 2 g per day.
Be sure to speak with your healthcare clinician before starting supplementation.
Side effects of L-carnitine?
Generally, L-carnitine is safe and has minimal side effects. Some people have noted they have experienced heartburn, diarrhea, indigestion and seizures.
Those who take L-carnitine supplements, be sure not to exceed 3 g per day as this can cause side effects.