Semaglutide vs Tirzepatide vs Retatrutide
A head-to-head comparison based on clinical trial data — weight loss percentages, receptor mechanisms, dosing protocols, and which compound is the right fit for your goals in 2026.
14.9%
Semaglutide (STEP-1)
22.5%
Tirzepatide (SURMOUNT-1)
24.2%
Retatrutide (Phase 2)
3
Compounds compared
Quick Summary
Not sure which compound to choose? Here's the short answer based on your primary goal.
Best First GLP-1
Semaglutide
Proven, well-tolerated, easiest titration
Best Overall
Tirzepatide
Phase 3 validated, superior dual-action efficacy
Best Efficacy
Retatrutide
Highest weight loss ever recorded in a clinical trial
Side-by-Side Comparison
Clinical data, receptor targets, dosing ranges, and product links for each compound.
Semaglutide
GLP-1 Agonist14.9%
weight loss
Best for
First-time GLP-1 users, T2D, proven safety profile
Tirzepatide
Dual GIP+GLP-122.5%
weight loss
Best for
Maximum efficacy with Phase 3 validation, best overall value
Retatrutide
Triple GLP-1+GIP+GCG24.2%
weight loss
Best for
Maximum efficacy, NASH, experienced GLP-1 users
Semaglutide
Semaglutide is the proven entry point into GLP-1 therapy. Targeting the GLP-1 receptor exclusively, it powerfully reduces appetite and delays gastric emptying. With 68 weeks of STEP-1 data behind it and FDA approval for both T2D (Ozempic) and obesity (Wegovy), it remains the most clinically documented option in the class.
- Proven GLP-1 receptor agonist — gold standard baseline
- Approved for T2D (Ozempic) and obesity (Wegovy)
- Well-understood titration and side effect profile
- Best entry point for GLP-1 naïve patients
- Easiest to source and most clinically documented
STEP-1 Trial Results
SURMOUNT-1 Trial Results
Tirzepatide
Tirzepatide's dual GIP+GLP-1 mechanism is what separates it from semaglutide. The GIP receptor co-agonism acts directly on fat cells and increases insulin sensitivity independently of appetite — explaining the 7-percentage-point superiority over semaglutide in head-to-head comparisons. With 72 weeks of Phase 3 data from SURMOUNT-1, it's the most validated non-semaglutide compound available.
- Dual agonist — GIP adds direct fat cell receptor action
- SURMOUNT-1: 22.5% mean body weight loss at 72 weeks
- Most clinically validated non-semaglutide option available
- GIP action works independently of appetite suppression
- Best overall efficacy-to-cost ratio in the GLP-1 class
Retatrutide
Retatrutide adds a third receptor — glucagon — to the GLP-1+GIP dual mechanism of tirzepatide. Glucagon receptor activation drives direct fat oxidation, thermogenesis, and liver fat burning, adding a metabolic layer absent in the other two compounds. At 24.2% mean body weight loss in Phase 2 trials, it produced the lowest body weight floor ever recorded in a peptide clinical trial.
- Triple agonist — adds glucagon receptor activation
- Highest weight loss in any clinical trial: 24.2%
- Glucagon drives fat oxidation and thermogenesis directly
- Addresses NASH and liver fat beyond other GLP-1 agents
- Lowest body weight floor achieved in all peptide trials to date
Phase 2 Trial Results
How to Choose
Match your situation to the right compound. These recommendations are based on clinical trial data, compound maturity, and user goals.
If you…
New to GLP-1 peptides
Proven, well-understood, easiest titration. The logical starting point.
If you…
Want maximum weight loss with Phase 3 data
SURMOUNT-1 is the largest and most rigorous GLP-1 trial available.
If you…
Want absolute maximum efficacy
Highest recorded weight loss. Suitable for experienced users comfortable with newer compounds.
If you…
Primarily struggling with appetite control
Both have robust appetite-suppression data. Tirzepatide adds GIP for extra fat-cell action.
If you…
Want metabolic/liver (NASH) benefits alongside fat loss
Glucagon receptor activation provides liver fat reduction beyond other GLP-1 agents.
Combining GLP-1 with GH Peptides
One of the most common protocols for experienced users is pairing any GLP-1 compound with Ipamorelin/CJC-1295. The reason is straightforward: aggressive fat loss from GLP-1 agents creates a significant caloric deficit, and without anabolic support, lean muscle mass is lost alongside fat.
Ipamorelin stimulates growth hormone release in a pulsatile, ghrelin-independent manner, preserving lean tissue during aggressive cuts. CJC-1295 extends GH half-life, making the combination significantly more effective than either alone. Together they act as an anabolic anchor during GLP-1 fat loss cycles.
Why Add GH Peptides?
Muscle preservation
GLP-1 creates a caloric deficit; Ipamorelin/CJC preserves lean mass during aggressive fat loss.
GH pulse optimization
Ipamorelin triggers natural GH pulses — no blunting of the natural axis, no cortisol spike.
Body composition
Users report improved fat-to-muscle ratio vs GLP-1 alone, even at identical weight loss.
Recovery support
CJC-1295 keeps GH elevated between pulses, supporting connective tissue and sleep quality.
Ready to Start?
Browse individual compounds or go straight to the GLP-1 fat loss stack that combines the best peptides for maximum results.
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