This is something I've been feeling really uneasy about. I personally have been stacking a tiny dose (0.3mg every six days) of Survo against a fairly low amount (5mg) of tirz weekly. I added the Survo because I've read a lot of people saying that it counteracts the tirz fatigue. I DO feel better and less tired, but I'm also troubled because ok, grey market tirz was fine, I'm reasonably sure it's the same thing as the compound I was taking with no problems. But I don't do reta because a) I'm uneasy about anything that revs the metabolism; I know it's not speed, but running a machine in a higher gear worries me and b) it's not all the way through trials yet and we have no info on the long term effects. And yet here I am effing around with Survo, which has both of those worry points for me.
I feel like the stack is something I likely won't be confident enough to do long-term, safety wise, and I'm soothing my anxious soul by reminding myself that it's a fairly tiny dose and it'll be hard to do significant unknown damage with that. But yeah, I'm nervous.