Semaglutide vs Tirzepatide
vs Retatrutide
Three generations of GLP-1-based peptides — each more potent than the last. This comparison covers mechanisms, clinical trial weight loss results, half-lives, and which compound wins for specific research goals.
Semaglutide
GLP-1 mono-agonist. Widest clinical dataset. Up to 15% weight loss at 68 weeks.
Shop Semaglutide →Tirzepatide
GLP-1 + GIP dual agonist. 22.5% weight loss at 72 weeks. Stronger than semaglutide.
Shop Tirzepatide →Retatrutide
Triple agonist (GLP-1 + GIP + glucagon). 24.2% weight loss at 48 weeks. Highest energy expenditure.
Shop Retatrutide →Side-by-Side Comparison
| Factor | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Receptor targets | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + Glucagon |
| Mechanism type | Mono-agonist | Dual agonist | Triple agonist |
| Peak weight loss (trials) | ~15% at 68 wks (STEP) | ~22.5% at 72 wks (SURMOUNT) | ~24.2% at 48 wks (TRIUMPH) |
| Half-life | ~168 hrs (7 days) | ~120 hrs (5 days) | ~6 days |
| Dosing frequency | Once weekly | Once weekly | Once weekly |
| FDA approval | Yes (Ozempic/Wegovy) | Yes (Mounjaro/Zepbound) | No (Phase 3) |
| Energy expenditure | Moderate (appetite only) | Higher (dual incretin) | Highest (adds glucagon thermogenesis) |
| Glucose control | Strong | Stronger | Strong |
| Lean mass preservation | Good | Better | Under investigation |
| Best for | Entry-level GLP-1 research | Superior weight + glucose | Maximum weight reduction |
Mechanism Deep Dive
Semaglutide — GLP-1 Only
Semaglutide activates the GLP-1 receptor, slowing gastric emptying, suppressing appetite via hypothalamic signalling, and improving postprandial glucose disposal. Its C18 fatty diacid conjugate enables albumin binding for a ~7-day half-life. The STEP trials established it as the benchmark GLP-1 peptide with the broadest human dataset of any agent in this class.
Shop Semaglutide →Tirzepatide — GLP-1 + GIP
Tirzepatide's dual GIP/GLP-1 agonism produces greater appetite suppression, improved insulin sensitivity through GIP-mediated pathways, and superior lean mass preservation versus semaglutide. The added GIP agonism potentiates GLP-1 activity rather than simply adding it — the interaction is synergistic. SURMOUNT-1 showed 22.5% weight reduction at the highest dose.
Shop Tirzepatide →Retatrutide — Triple Agonist
Retatrutide adds glucagon receptor agonism on top of GIP and GLP-1 — the glucagon component drives hepatic fatty acid oxidation and thermogenesis, increasing energy expenditure independently of appetite. This is why Phase 2 TRIUMPH data shows 24.2% weight loss at 48 weeks — a shorter trial period with greater results than either predecessor.
Shop Retatrutide →Which Peptide Wins For Each Goal?
Maximum weight loss
Retatrutide
Triple agonism drives the highest documented weight reduction in clinical trials (24.2% at 48 weeks).
Best human clinical data
Semaglutide
Largest Phase 3 dataset of any GLP-1 peptide — STEP 1–5 plus cardiovascular outcome data (SUSTAIN-6, SELECT).
Glucose control + weight loss
Tirzepatide
Dual GIP/GLP-1 produces superior glycaemic control versus semaglutide in head-to-head SURPASS trials.
Energy expenditure / thermogenesis
Retatrutide
Glucagon receptor agonism increases basal metabolic rate through hepatic thermogenesis — not achievable with GLP-1 or GIP alone.
First-line GLP-1 research
Semaglutide
Most well-characterised pharmacology, widest dose range studied, and established safety profile from FDA-approved clinical use.
Stacking with amylin agonists
Semaglutide
The CagriSema combination (Semaglutide + Cagrilintide) achieved ~20% weight loss targeting complementary pathways — the most studied GLP-1 combination.
Frequently Asked Questions
Which is stronger: Semaglutide, Tirzepatide, or Retatrutide?
Clinical trial data shows Retatrutide produces the greatest weight loss (24.2% at 48 weeks), followed by Tirzepatide (22.5% at 72 weeks), then Semaglutide (~15% at 68 weeks). Each additional receptor target adds a distinct mechanism that increases total metabolic effect.
Can you stack these GLP-1 peptides together?
Stacking GLP-1 agonists with each other is not studied and would be redundant — they compete for the same receptor. However, combining a GLP-1 agonist with a complementary agent (e.g. Semaglutide + Cagrilintide for amylin pathway synergy) is actively researched.
What is the half-life of each peptide?
Semaglutide: ~168 hours (7 days). Tirzepatide: ~120 hours (5 days). Retatrutide: ~6 days. All three support once-weekly subcutaneous dosing.
Is Retatrutide approved by the FDA?
No. Retatrutide is in Phase 3 trials as of 2026. Semaglutide (Ozempic/Wegovy) and Tirzepatide (Mounjaro/Zepbound) are FDA-approved. All three are available as research peptides for laboratory use only.
Research use only. All products sold by JA Performance are strictly for laboratory and in vitro research purposes. Not for human consumption, medical use, or veterinary use.