ive never used anything but prop, but i would STONGLY ADVISE NOT USING IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!! maybe they have other good products as satch would say, but that prop i got 3 outa 3bottles were contaminated, i used one shot from one bottle it got infected, 2weeks later after i got of my BIO's i started again took another from the other bottle it got infected to, and im not an idiot i know how to prep! i was preping for EQ at the same time and those sites were fine, and even if i was an idiot and didnt remeber to clean my hands after wiping my ass and injecting myself that 3rd bottle, wich was my friend the first and only shot he took of it got him a nice leg absess that winded him in the hospital, which is how every one found out he was on shit, so i did not hav a good experience with GTP, but knock yourself out...