Gingko is one of the oldest plants on Earth. It predates the dinosaurs. The fashion of smart drugs came and went pretty fast, but of those which ever gained any credibility, gingko was the belle of the ball, and most studied.
Now it seems that gingko does have some effect as a memory enhancer, but wouldn’t really do much for people operating at their higher levels of mental efficiency.
It’s been considered possibly useful for people with declining mental abilities or diseases, but even that has now been torpedoed to some extent by a memory test in which placebo users outperformed gingko users.
There are also identified risk factors in using gingko, notably in combination with things like aspirin, or blood thinners. Gingko is know to stimulate blood circulation, and the risk of bleeding may be increased.
This article is a pretty highly qualified series of statements about the miracle drug of the late 90s. It’s very much a matter of opinion if the health supplements industry has any more conscience or scientific method than the most iffy of conventional fad medicines.