Long term studies haven't shown any harm. I've taken 30g a day for well over a year now for both the physical performance and the cognitive benefits. I had brain fog following a bad COVID infection which this has helped with. My family also has a history of Alzheimer's and dementia (both sides), I figure it can't hurt.

The only side effects I've encountered have been mild GI discomfort, and that only rarely (mostly when restarting after a vacation etc-- I drop the routine when I travel). Roughly similar to having a morning coffee at its worst.

I've found I get much thirstier when on this high of a dose. If you're not already a big water drinker I'd definitely invest in a nice insulated bottle to drag around.