What is acetyl-L-carnitine
Acetyl-L-carnitine, also known as ALCAR, is a well-researched nutritional supplement. It is synthesized to provide a more bioavailable form of L-carnitine, which is a derivative of the amino acid lysine. L-carnitine is made naturally in the body by the liver and kidneys, and then transported to other tissues such as the brain and heart. Like L-carnitine, acetyl-L-carnitine functions as an antioxidant and promotes the production of glutathione, a free radical scavenger, in cells.
Why is it necessary?
Because L-carnitine is involved in cellular metabolism, acetyl-L-carnitine can help increase energy production in the mitochondria, the "power plants" of all cells, and thereby may generally boost physical and mental energy. As a dietary supplement, acetyl-L-carnitine is often used to help improve memory, and has been studied as a possible adjunct treatment for Alzheimer's disease. Acetyl-L-carnitine may also help address symptoms of depression, and may be useful in the treatment of Parkinson's disease, stroke, and Peyronie's disease. In addition, daily supplementation with acetyl-L-carnitine may have a protective effect on the central nervous system and may benefit the heart. There is also some evidence that acetyl-L-carnitine can enhance visual memory and attention in people with Down Syndrome, and clinical data indicates that it also may slow age-related mental decline that is not associated with Alzheimer's.
What are the signs of a deficiency?
Healthy people usually synthesize enough L-carnitine to avoid a deficiency.
How much, and what kind, does an adult need?
Dr. Weil recommends 500 to 1,500 mg per day.
How much does a child need?
Children should not take supplemental acetyl-L-carnitine.
How do you get enough from foods?
The principal dietary source of acetyl-L-carnitine is red meat, in particular mutton.
Are there any risks associated with too much?
Side effects include mild gastrointestinal symptoms, such as nausea, vomiting, and abdominal cramps, as well as headache; an increase in agitation or restlessness; and an increase in seizure frequency in persons with seizure disorder. Persons with Alzheimer's disease may exhibit psychiatric disturbances, such as depression and confusion, but it is uncertain whether these effects are due to acetyl-L-carnitine or the disease itself. Some evidence suggests acetyl-L-carnitine may interfere with thyroid metabolism.
Are there any other special considerations?
- To offset any temporary gastointestinal effects, take acetyl-L-carnitine with food.
- If you have gastroesophageal reflux disease (GERD), consult your healthcare professional before taking acetyl-L-carnitine.
- Pregnant and lactating women are advised not to consume acetyl-L-carnitine.
Updated by: Andrew Weil, M.D., and Brian Becker, M.D., on Sept. 5, 2012
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