If you can only get one, then I'm with T&H, tirzepatide is proven, works well, there's copious info on the web about using it off-label as we all are, and even info specific to the "generic formulations" which most everyone is using. I lost 20kg on Chinese tirzepatide; shit works.
More than for weight loss, I'm messing with retatrutide due to a mild mental disorder -- having to have new things and hoarding disguised as collecting.
I disagree with T&H on the reta starting dose though, and there are options. The Phase 3 study is doing the same thing that the Phase 2 was, l believe. Starting doses of 1, 2 or 4mg, Basically that's there in case you have some discomfort when starting, as many do, but I think it's mostly chicks. If you're willing to risk some gastro issues, you could start at 4. If you're willing to risk it just a little, you can start at 2. The most conservative is 1mg. Once you get to 4 and would jump to 8, then 12 (max). Once at 4mg you do want stay at each dose for at least a couple of weeks (testing was doing 4w, I believe, but it's searchable) to titrate up. But if you do OK on 1mg for a week, I wouldn't see any issue going to 2 the next. And if 2 goes well, jump straight to 4. You won't see any weight loss at 1 or 2, but you will see if you're going to literally shit yourself
If you can swing it financially, and aren't in a huge rush, then I'd get the reta, and if it doesn't work for you, switch to tirzepatide -- but I realize it's easy to spend other people's money.
Good luck on your journey, and be sure to read any and everything you can on the topic. Don't hesitate to ask questions on Meso. Most people here are dickheads, but they're helpful dickheads. You'll be on Tren before the end of the year.
GPB