well at the time it was spawned late 60's early 70's i dont remember, the hex ester was, what the french company that manufactured it, used for whatever reason before the company went under or whatever the story was... the parent hormone is still tren... if anything at least back then with the pharm grade you knew it was being made to spec due the extent of involvement, nowadays its really only on the word of the raw source unless someone risks getting a now controlled substance at least in the US, tested for analysis and purity etc since nobody is producing for USP grade medicinal purposes, again... yet