How it Works: Ginkgo regulates blood vessel health, increasing blood flow to the brain. Its antioxidant compounds scavenge free radicals and proteins that can accumulate in memory-robbing dementias. Ginkgo also inhibits blood clots that could block vessels.

The Lowdown: Ginkgo may improve mental performance in healthy individuals as well as in those with established dementia. In one study, healthy volunteers taking ginkgo combined with Panax ginseng enjoyed sharper cognitive function and less mental fatigue than volunteers who did not take the supplements. They also had temporary improvement in short- and long-term memory.

Expert Testimony: "Ginkgo may slow down the dementia illnesses," says Edelberg. "However, if your memory is already pretty sharp, don't expect significant improvement."

Did You Know? Be thankful that ginkgo is available in pill form; for millennia, people resorted to brewing tea from the notoriously stinky leaves.

Suggested Dose: Take 60 mg standardized extract of ginkgo biloba (GBE) twice daily."