Honestly, if I were you, and felt this way. I mean if you didn't know which one to use. Start out with one, run it for a while. Come off, and then run the other. With Lab work done, before and after, each one.
After all, we are our own Guinea Pigs. I mean carefully sort through the information, and if you still feel that way, that's what I would do. I started out on Tirz because Reta wasn't really out like that. Then jumped on Reta to see what it is like.
To me, I can run either one for insulin/glucose control with GH. But an added safety measure, I take an SGLT 2 (jardiance) with my shot. I like Reta better because I can do recomps better, my muscles stay fulller, I can eat more carbs, etc.. To me it's a better one for ppl who workout, just my opinion, and from my trainees standpoint because of the preservation of muscle factor. Overall weight loss, I think Tirz is better, to me. That's just my take on which is better.