The recommended supplemental dosage of PQQ is 10-20 mg a day.
You would have to eat 350-700 pounds of natto a day to reach that level of PQQ intake. (Source.)
How is such radically unnatural intake of this vitamin justifiable?
Lots of unnatural things are justifiable.
The more obvious example is in those missing something in their bodies. Supplemental thyroid hormone for those with thyroid dysfunction, supplemental insulin for type 1 diabetics.
In the PQQ case, if the goal is to achieve health benefits from supraphysiological doses, than the ends would justify the means. Of course the rub is that there isn't a ton of long-term evidence for unnatural dosages of PQQ, resveratrol, and friends. Personally, I tend towards the precautionary principle. People have been proven wrong throughout history when they mess around with large amounts of stuff. I don't feel confident in my ability to jump from selective research findings to guessing how my body will handle things over large periods of time.
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