I've read that the dietary supplement acetyl-L-carnitine may reduce fatigue in multiple sclerosis. Is this true?
Answers from Jerry W. Swanson, M.D.
Some research suggests that acetyl-L-carnitine can improve fatigue associated with multiple sclerosis (MS), although more study is needed.
Acetyl-L-carnitine is a form of L-carnitine, an amino acid that is found in nearly all cells of the body. L-carnitine plays a critical role in the production of energy from long-chain fatty acids. In addition, it increases the activity of certain nerve cells in the central nervous system.
Fatigue is a common symptom in people with multiple sclerosis. The cause isn't well understood. A study published in 2006 evaluated the benefit of supplementation with L-carnitine in people with MS-related fatigue who had low blood levels of L-carnitine. Study participants were given 3 to 6 grams of oral L-carnitine daily. Researchers reported a decrease in fatigue intensity in 65 percent of participants treated with immunosuppressive drugs, especially in those treated with cyclophosphamide and interferon beta. Another study published in 2004 showed that acetyl-L-carnitine seemed to improve fatigue in people with MS better than amantadine, a drug commonly used to treat MS-related fatigue.
However, problems with the design of these studies make it unclear whether acetyl-L-carnitine is truly effective at reducing MS-related fatigue. A recent systematic review published in 2012 concluded that there is still insufficient evidence that carnitine offers a therapeutic advantage over placebo or other medications. An ongoing larger scale randomized, placebo-controlled clinical trial expected to be completed in 2013 may answer some of these questions.
Although acetyl-L-carnitine generally has few or mild side effects, it can interfere with anticoagulants and other medications. So talk to your doctor before starting acetyl-L-carnitine or any dietary supplement.
Sep. 07, 2012
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- Lebrun C, et al. Levocarnitine administration in multiple sclerosis patients with immunosuppressive therapy-induced fatigue. Multiple Sclerosis. 2006;12:321.
- Tejani AM, et al. Carnitine for fatigue in multiple sclerosis. Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007280.pub3/abstract. Accessed August 2012.
- Tomassini V, et al. Comparison of the effects of acetyl L-carnitine and amantadine for the treatment of fatigue in multiple sclerosis: Results of a pilot, randomised, double-blind, crossover trial. Journal of the Neurological Sciences. 2004;218:103.
- Levocarnitine. Micromedex Healthcare Series. http://www.micromedex.com. Accessed July 23, 2012.
- Pirko I (expert opinion). Mayo Clinic, Rochester, Minn. Aug. 3, 2012.