Ginseng fails to increase energy, immunity in tired people, study finds

Ginseng is touted as an energy and immunity booster, but the popular herb didn’t do much for healthy volunteers who took it for eight weeks.

Previous studies didn’t look at the energizing effects of ginseng on people who were already tired, says lead author Hermann J. Engels, associate professor of exercise physiology at Wayne State University in Detroit. So he and his colleagues asked 27 students to do repeated bouts of strenuous exercise, both before and after an eight-week regimen of ginseng or a placebo.

The volunteers did three intervals on a stationary bicycle separated by brief rest periods. At intervals throughout their cycling and during the recovery periods, researchers tracked the volunteers’ level of exertion and heart rate recovery. Saliva was collected before and after exercise and tested for secretory immunoglobulin A, a protein that protects mucous membranes against cold viruses.

The exhausting exercise diminished levels of secretory immunoglobulin A both for those who had taken ginseng and for those who had taken a placebo. And there was no difference between the groups in measures of performance or fatigue. Both groups also had the same number of colds.

The study was published in the April issue of Medicine & Science in Sports & Exercise.

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Dianne Partie Lange