THE REALITY: Ginseng, a supplement typically derived from an Asian plant, has been used for centuries and is currently one of the most popular herbal products in the United States. Products with ginseng often purport to enhance cognitive powers and some say they can stave off age-related mental declines.

In an analysis published this month, several researchers took a look at these claims from a scientific perspective. But rather than undertaking their own study the researchers looked at all of the reputable published studies to try to assess whether there was evidence of ginseng’s brain-boosting power.

What they found was mixed. Overall, there are very few good studies on the effects of ginseng, and those that have been done show mostly inconclusive results. In particular, the researchers found no evidence for ginseng’s effect on dementia or other age-related mental decline.

However, there was some evidence showing that the herb may improve reaction time and working memory, the short-term memory you use when working on a specific task. Though the evidence was not airtight, a number of studies pointed to the herb’s effect on these two aspects of cognition.

The bottom line: Ginseng may boost brain power, for some parts of your brain.

— Betsy Q. Cliff, The Bulletin