yep, the IP6 really stressed my kidneys. I was taking it in the heat of summer, I was sweating more than peeing. Even though SOME of the same things are excreted in sweat as in urine, not ALL are, and one excretes MORE of these substances in the urine.
So, even though I was staying VERY well hydrated, the IP6 stressed my kidneys due to the fact that the fluid output was relatively low.
That's my take on it anyway.
I'll have another go at the IP6 one of these days, the data on the stuff is most impressive:)