UPMC Study on Ginkgo
There were early indications that Ginkgo has antioxidant and other properties that might preserve memory, this trial shows that it does not. It also didn’t affect the rate of coronary heart disease or stroke.
It’s possible that an effect would have been observed, if the study had gone on longer, because it takes many years to progress from initial brain changes to clinical dementia. That study is now underway.