Carnitine is derived from an amino acid and found in nearly all cells of the body. Its name comes from the Latin word carnus, meaning flesh, as it was isolated from meat. Carnitine plays a critical role in the production of energy. It transports long-chain fatty acids into the mitochondria so they can be oxidized, or burned, to produce energy. Carnitine also transports toxic compounds out of the cellular organelle, preventing any accumulation. Given these functions, carnitine is concentrated in tissues like skeletal and cardiac muscle that utilize fatty acids as a dietary fuel. For most people, the body makes a sufficient amount of carnitine. However, some people have genetic or medical conditions that prevent their bodies from meeting the necessary needs. This is when supplementation is essential.
Carnitine can be found in animal food sources such as meat, fish, poultry, and milk. Carnitine occurs in two forms known as D-carnitine and L-carnitine. They are isomers (or mirror images) of each other. L-carnitine is the active form found in the body and found in food. Carnitine is absorbed in the small intestine, in turn, entering the bloodstream. Those who eat a diet that includes red meat and other animal products typically obtain about 60-180 milligrams of carnitine per day.
Carnitine is indicated in those with cardiovascular disease, renal (kidney) insufficiency, male infertility, diabetes, muscular disease, HIV/AIDS, and it also helps aid in athletic performance and aging.
There are no known side effects of carnitine when taken in normal doses. Some reported side effects include:
- – Nausea
- – Vomiting
- – Diarrhea
- – Stuffy nose
- – Restlessness
- – Insomnia
- – Body odor (“fishy” smell)
Some serious side effects may include:
- – Tachycardia (fast heart rate)
- – Hypertension (increased blood pressure)
- – Fever
There are no reported contraindications for carnitine. However, you should always speak with your doctor before taking carnitine.
According to National Institutes of Health, carnitine interacts with pivalate-conjugated antibiotics such as pivampicillin which are used in the treatment of urinary tract infections. Taking these antibiotics increase the excretion of pivaloyl-carnitine, which can lead to carnitine depletion. Carnitine also interacts with the anticonvulsants valproic acid, phenobarbital, phenytoin, or carbamazepine. Taking these have been shown to significantly decrease blood levels of carnitine. In addition, the use of valproic acid with or without other anticonvulsants may cause hepatotoxicity and increase plasma ammonia concentrations, leading to encephalopathy.
Carnitine is FDA approved and available over-the-counter as a dietary supplement. Carnitine is available in two forms: oral and injection. It is often promoted as a weight loss aid to help improve exercise performance and enhance one’s sense of well-being. It is important to speak with your physician before taking any supplemental drugs.