- L-carnitine is an amino acid (a building block for proteins) that is naturally produced in the body.
- L-carnitine supplements are used to increase L-carnitine levels in people whose natural level of L-carnitine is too low because they have a genetic disorder, are taking certain drugs (valproic acid for seizures), or because they are undergoing a medical procedure (hemodialysis for kidney disease) that uses up the body’s L-carnitine. It is also used as a replacement supplement in strict vegetarians, dieters, and low-weight or premature infants.
- L-carnitine is used for conditions of the heart and blood vessels including heart-related chest pain, congestive heart failure (CHF), heart complications of a disease called diphtheria, heart attack, leg pain caused by circulation problems (intermittent claudication), and high cholesterol.
- Some people use L-carnitine for muscle disorders associated with certain AIDS medications, difficulty fathering a child (male infertility), a brain development disorder called Rett syndrome, anorexia, chronic fatigue syndrome, diabetes, overactive thyroid, attention deficit-hyperactivity disorder (ADHD), leg ulcers, Lyme disease, and to improve athletic performance and endurance.
- The body can convert L-carnitine to other amino acids called acetyl-L-carnitine and propionyl-L-carnitine. But, no one knows whether the benefits of carnitines are interchangeable. Until more is known, don’t substitute one form of carnitine for another.
- L-carnitine helps the body produce energy. It is important for heart and brain function, muscle movement, and many other body processes.
- L-carnitine is LIKELY SAFE for most people when taken by mouth and when used as an injection, with the approval of a healthcare provider. It can cause side effects such as nausea, vomiting, stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a “fishy” odor.
- Pregnancy and breast-feeding: There is not enough reliable information about the safety of using L-carnitine if you are pregnant. Stay on the safe side and avoid use. Taking L-carnitine is POSSIBLY SAFEin breast-feeding women when taken by mouth in the amounts recommended. 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 taken by a breast-feeding mother are unknown.
- Children: L-carnitine is POSSIBLY SAFE when used appropriately by mouth or intravenously (by IV), short-term.
- Under-active thyroid (hypothyroidism): Taking L-carnitine might make symptoms of hypothyroidism worse.
- Kidney failure: Using DL-carnitine has been reported to cause symptoms such as muscle weakness and eye drooping when administered intravenously (by IV) after dialysis. L-carnitine does not seem have this effect.
- Seizures: L-carnitine seems to make seizures more likely in people who have had seizures before. If you have had a seizure, do not use L-carnitine.
Moderate Interaction Be cautious with this combination:
- Acenocoumarol (Sintrom) interacts with L-CARNITINE: 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 interacts with L-CARNITINE: 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) interacts with L-CARNITINE: 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.
3-carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium inner salt, (3-carboxy2-hydroxypropyl) trimethylammonium hydroxide inner salt, 3-hydroxy-4-N-trimethylaminobutyrate, B-hydroxy-N-trimethyl aminobutyric acid, Beta-hydroxy-gamma-trimethylammonium butyrate, B(t) Factor, Carnitine, Carnitor, D-Carnitine, DL-Carnitine, Facteur B(t), L-3-hydroxy-4-(trimethylammonium)-butyrate, Levocarnitine, Lévocarnitine, Levocarnitine Fumurate, 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).
Source: WebMD, “L-Carnitine”, www.webmd.com/vitamins-supplements/