Yeah, but it will convert to other types of estrogen as well, not just estradiol so the "balance" is better. He might get away with using a small amount of that along with a AI. I know your against AI's per se bu when/if he is injecting estrogen along with test that already boosts it, he will need it. Also there must be better gear out there in Mexico than this cattle profit injection..
5mg of estrogen isnt going to cause problesm though. and even if it did cause a problem, what would that be? a bit of gyno.. thats about it. besides that, it would slightly help with anabolism. so its a small trade off.
if the option is NO GEAR, or GEAR WITH 5MG ESTROGEN..... id choosse the second any day of the week. anyone who would choose no gear over gear with estrogen is ignorant, plain and simple.