NEW YORK (Reuters Health) - The popular supplement L-carnitine doesn't help cancer patients with fatigue, according to a new study.
L-carnitine is an amino acid naturally produced by the body and helps cells convert fats into energy.
U.S. health regulators have approved the substance as treatment for deficiencies caused by genetic diseases and to boost red blood cells in people with serious kidney disease. However, it's also used for a variety of other conditions where the medical evidence is shaky at best.
In the new study, published in the Journal of Clinical Oncology, researchers pitted the supplement against a placebo to see if it would help cancer patients with moderate or serious fatigue.
Over four weeks, 163 patients downed two grams of L-carnitine daily while another 170 patients gulped downed an inactive liquid. In stores, the amino acid can be bought as liquid, tablets or capsules for about $20 to $50 for a three-month supply.
The research team, led by Dr. Ricardo Cruciani of Beth Israel Medical Center in New York, tested the patients at the outset of the study and again at the end of the four weeks.
On a fatigue scale from 0 to 10, both placebo-treated patients and those who took the amino acid improved by about one point. Even those patients who were carnitine-deficient at the outset of the study did not feel any less tired when they got the supplement than when they didn't.
The researchers also used a variety of other measurements - including another fatigue scale, a depression scale and a pain scale - to make sure they hadn't missed any beneficial effects. They found no differences between the two groups.
The study does have limitations, however. At least a quarter of the participants did not complete their follow-up assessments, so it's unclear if they got any benefits from L-carnitine.
Cruciani did not respond to requests for comment.
SOURCE: bit.ly/P0nI8q Journal of Clinical Oncology, online September 17, 2012.