Good question, and honestly the answer is more interesting than people expect because these three compounds don't suppress appetite the same way at all, even if the end result on the scale looks similar.
My personal ratings, 1-10:
Semaglutide: 6/10. Solid, steady, kind of a "background" suppression. You notice you're just not thinking about food as much, but if food is in front of you, you'll still want it. Cravings stay mostly intact.
Tirzepatide: 8/10. This one is on another level for pure appetite shutdown. The GIP component seems to amplify the satiety signal hard. I'd get full from half a plate and the thought of eating more felt almost physically off-putting. Strongest hunger killer of the three by a clear margin in my experience.
Retatrutide: 5/10. And this is where it gets interesting, because on paper you'd expect reta to suppress the most, given it's a triple agonist. But the appetite suppression itself is actually milder than tirze for me, and a notch below sema too.
So why is reta still working so well if the hunger suppression is the weakest of the three? This is where the glucagon agonism completely changes the game, and I think a lot of people miss this when they compare compounds purely on "how much does it kill hunger."
What I notice on reta that I didn't get on the other two:
No alcohol cravings at all. Like, zero pull. Sema and tirze reduced it a bit, but with reta the desire just isn't there. There's actually emerging literature on GLP-1s and reward pathways (a lot of the addiction/alcohol use disorder trials are running on sema and tirze right now), but anecdotally reta hits this harder for me. Might be the glucagon component amplifying the dopaminergic effects, might be something else, but the effect is real.
Sweet cravings are way down. Sema and tirze killed hunger but I still wanted sweets specifically. On reta the actual desire for sugar isn't there. Big difference between "I'm not hungry" and "I genuinely don't want that donut." Reta does the second one.
Energy is noticeably higher. This is the glucagon receptor agonism doing its thing. Glucagon increases hepatic glucose output and bumps up resting energy expenditure, basically your body is running a bit hotter. You feel it. On sema and tirze in a deficit I'd get the typical lethargic, cold-hands, low-energy diet feeling. On reta I'm in a deficit and I still feel like training, still warm, still sharp. That's a huge quality-of-life difference when you're cutting.
So the way I'd frame it for anyone choosing between them:
If your problem is pure volume of food / can't stop eating, tirze is the strongest tool.
If you want steady, sustainable, mild suppression with a good safety record, sema.
If your problem is cravings (alcohol, sweets, reward-driven eating) and you want to actually feel good while losing fat, reta is in a different category.
The appetite number doesn't tell the whole story with reta. It's working on the metabolic side as much as the appetite side, and that's why people are getting these crazy recomp results even at modest doses.