Coffee is pretty amazing. I self experimented with ginkgo biloba (10 yrs of two year on - two year off) and noticed nothing. The only things that have very noticeable effect on my alertness and energy are, in order, exercise, sleep, coffee. I avoided coffee for many years because it seemed to aggravate an irregular heartbeat. But when the irregularity came on despite zero caffeine I went back to one cup every morning. (Cardiologist has since cleared me. Rogue beats are apparently not that uncommon in the population.)