u/Woke100

Weight loss is the most asked-about topic here, and the confusion is always the same: people compare these like they all do the same job. They don't. Here's the full roster in plain language, what each one actually does to your body, and who should reach for it. Find yourself in the list.

Semaglutide (Ozempic, Wegovy) 
What it does: mostly works on appetite and fullness, plus it slows down how fast your stomach empties, so the main effect you feel is eating less without white-knuckling cravings all day. It's not a metabolism booster, it's a hunger reducer. Around 15% of body weight lost in trials. Weekly injection. Main side effects are nausea and constipation, worst when you raise the dose. You'll notice appetite drop in 1 to 2 weeks, real weight loss over 3 to 4 months. (It's a GLP-1, the original of this class.) Who should lean toward it: you've got weight to lose and you want the option with the longest safety record and the most people who've used it, even if it's not the strongest. A solid, cautious first choice.

Tirzepatide (Mounjaro, Zepbound) 
What it does: same appetite-killing effect as semaglutide, but it hits a second hunger pathway on top of the first, so it works noticeably stronger. People lose more on it, around 21 to 22% in trials, and when the two were tested directly against each other, it won (20.2% vs 13.7%). Weekly injection, same nausea/GI side effects, tolerated about the same. (Adds a receptor called GIP, which is why it's a "dual" agonist.) Who should lean toward it: you want the most weight loss you can actually get prescribed right now, or you tried semaglutide and it wasn't enough or stopped working. For most people serious about real weight loss with approval behind it, this is the current best pick.

Retatrutide 
What it does: same appetite suppression as the other two, but it adds a third effect, it nudges your body to burn more energy, not just eat less. So you're getting hunger reduction plus a metabolic boost at the same time, which is why it's posting the biggest numbers anyone's seen, around 24% in earlier trials and about 28% in the latest one. The catch: it's still in clinical trials and not approved, so the only way to access it is through a trial, not a prescription or a compounding pharmacy, and there's less long-term safety data. Weekly injection, and it has the most intense nausea/GI of the three. (It's a "triple" agonist, adding a hormone pathway called glucagon.) Who should lean toward it: you're chasing the absolute highest weight loss possible and you've likely already maxed out tirzepatide, and you accept that it's unapproved and less proven. Not your move if you want the safe, established route.

Liraglutide (Saxenda, Victoza) 
What it does: the older version of semaglutide. Same appetite-reducing idea, but you have to inject it every day instead of once a week, and it works less well, roughly 5 to 8% in real-world use. You build up to the full dose over about 5 weeks. Who should lean toward it: realistically only if you already have it, tolerate it well, or can't get the newer weekly options. For most people it's been replaced. Worth knowing it exists, rarely the first choice now.

Tesamorelin 
What it does: this one does NOT touch your appetite. It works completely differently, it raises your body's growth hormone, and its specific job is shrinking visceral fat, the deep belly fat packed around your organs (different from the soft fat you can pinch). It's not for dropping overall scale weight, it's for that hard, deep gut. Around 15 to 20% reduction in that deep fat over about 6 months. Daily injection, taken on an empty stomach. Side effects are mostly injection-site irritation and some water retention. Slow to show, this is a months-long play. One important note: it's FDA-approved specifically for visceral fat in people with HIV-related fat changes. For general "I want my deep belly fat gone" use, it's off-label / research-context, not a broadly approved belly-fat drug. Who should lean toward it: your weight is roughly where you want it but you've got a stubborn hard belly that won't go, or you've already lost weight on a GLP-1 and the midsection is the last holdout. You're targeting deep belly fat specifically, and it's often run alongside a GLP-1, not instead of one.

CJC-1295 and Ipamorelin 
What they do: also not appetite drugs. They bump up your own growth hormone in natural pulses, which helps you hold onto muscle, recover better, and slowly improve body composition. They're not real fat-loss drivers, there are no weight-loss trials behind them, and the muscle-saving benefit is more theory-from-how-GH-works than directly proven. Daily, usually before bed. Mild side effects. Who should lean toward them: you're already losing weight (usually on a GLP-1) and you're worried about losing muscle along with the fat. This is a muscle-protection and recovery add-on during a cut, not something that drives weight loss on its own.

AOD-9604 
What it does: it's a piece of the growth hormone molecule, meant to trigger fat burning directly without the other growth-hormone effects. That's the theory. In practice the human evidence is weak, one study showed about 2.6 kg lost vs 0.8 kg on placebo over 12 weeks, others showed basically nothing, and a review concluded it doesn't meaningfully work in humans. Small results at best. Daily, over 6 to 8 weeks. Who should lean toward it: honestly, almost nobody as a main tool. If you specifically want a non-appetite, direct fat-burning approach and you understand the evidence is thin and the results small, it's a minor add-on at most. Not for anyone who wants reliable, real weight loss.

5-Amino-1MQ 
What it does: a pill, not an injection. It blocks an enzyme that's overactive in fat cells, which in theory frees those cells to burn more fat and raises your cellular energy (NAD+), all without touching your appetite. In mice it caused fat loss without them eating less. The problem: there are no human weight-loss studies at all yet. Usually taken as 50 to 100 mg twice a day. Who should lean toward it: you want an oral, no-needles option with an energy/metabolism angle and no appetite effect, and you fully accept it's almost completely unproven in people. An experiment, not a dependable tool.

MOTS-c 
What it does: a peptide that acts like an "exercise signal," it switches on a pathway (AMPK) that improves how your body handles energy and stamina. In mice it improved insulin sensitivity and reduced obesity, but in humans the research is very early and about metabolic health and endurance, not weight loss. No real human weight-loss data. Who should lean toward it: someone interested in metabolic health and endurance support, not someone trying to lose weight. Don't pick this for the scale.

PYY 
What it does: a natural "I'm full" hormone your gut already makes. On its own it doesn't work well as a weight-loss drug because it doesn't last long in the body. But a 2024 study found that adding it to semaglutide beat semaglutide alone, so its real future is probably as a sidekick to a GLP-1, not a standalone. Who should lean toward it: nobody yet as a solo option. Worth watching as a future add-on to a GLP-1, not something to run by itself.

If you're stuck between two 
These are the matchups people actually get hung up on.

Semaglutide vs tirzepatide: want the stronger result and can get it? Tirzepatide, it won head-to-head. Go semaglutide only if cost, access, or a longer comfort history matters more to you than maximum loss.

Retatrutide vs tirzepatide: tirzepatide if you want approved, available, and proven. Retatrutide only if you've truly plateaued on tirzepatide and you're willing to run something still in trials for the extra few percent. For most people, tirzepatide is the answer and reta is the "maybe later" option.

GLP-1 vs tesamorelin: the one people get most wrong, because it's not either/or. Got weight to lose? A GLP-1. Weight's fine but the deep belly won't budge? Tesamorelin. Both problems? That's the case for running them together, not choosing between them.

GLP-1 alone vs GLP-1 plus a GH peptide: only add CJC/Ipamorelin or tesamorelin if muscle loss or a stubborn midsection is your specific concern. If you just want the weight down, the GLP-1 alone does the heavy lifting.

Which one are you leaning toward, and what's the goal you're actually chasing? Stuck between two? Drop them below and people can weigh in.

Seeing a lot of the same beginner questions lately so figured I’d repost this for newer people in here.

bodyhackguide.co

Has a bunch of peptide breakdowns, calculators, dosing/reconstitution stuff, and general recovery info all in one spot.