im assuming the metabolites or chemical produced is actually a minuscule amount of pyrrolidine which is toxic. but only if the substance is burned (Can't remember the scientific term... pyrolysis?) It seems to nail the kidneys and nail them hard. I recommend massive fluid intake on binges, orange juice calcium and honey to help your kidneys. be very careful when vaporizing if it turns a very dark amber-black stop smoking always clean the pipes after a few doses. If you inhale to much of the burned shit you will notice some very nasty effects on your body later on in the binge. skin discoloration, I've experienced burning tingling itching flashes of extreme heat in areas feelings of bone joint and muscle pain urinary retention bad GI issues, surprisingly not so much with chest discomfort or breathing issues maybe slightly there. so I chalk all that up to large amounts of pyrrolidine causing kidney dysfunction and causing nerve issues because of the toxic build up from poor kidney function. I have yet to notice cola colored or red colored urine, bad smelling urine, or swelling from fluid retention. and to answer immad's question couldn't tell you never got to try mdpv. however I did get to try what I believe was A-pvp (white crystals strong vinegar smell) had a very similar yet distance taste of php but absolutely blew php out of the god damn exosphere in terms of awesome