hey bro
reason is simple and a debatable one as well, some say tren is much harsher then other substances such as test and deca.....there have been many bros (myself included) who have ran tren 10 weeks or more and have been fine, when i say fine i say bloodwork being done....whether it is or it isnt that much more harsh who knows just make sure you keep it within reason and conduct tests to make sure things are within normal ranges.....peace