People have been taking ginseng for millennia, long before modern scientific methods were around to prove it had the health benefits they expected. There still hasn’t been much high-quality research done on ginseng, the type where scientists randomly assign people to take the supplement or a placebo and see what happens. What we do have isn’t encouraging. A review of the studies done before 2010 concluded there was “a lack of convincing evidence” that ginseng had any brain-boosting effects. Scientists who evaluated the evidence in 2014 still thought it was “premature” to come to any conclusions. The nail in the coffin: The supplements you’re buying may not even have ginseng in them, scientists found when they analyzed DNA from supplements sold at major chain stores and checked their findings against the labels.