I don't feel it's necessary to supplement given my green tea intake.
"PQQ is mostly contained in common foods; comparatively in large quantities in natto (fermented soybeans), tea, papayas, and kiwi fruits"
http://www.brain.rik...qq/index-e.html
"Since PQQ is contained in many kinds of foods, as long as you have usual eating habits, the possibility of PQQ shortage is quite low (ref. Q7). Therefore, you do not need to take PQQ from some supplements."
http://www.brain.rik...q/faq-e.html#10
