Peptide comparison
All three are the vanguard of the metabolic family, but they differ in something essential: how many receptors they activate. Semaglutide agonizes one (GLP-1), tirzepatide two (GIP and GLP-1) and retatrutide three (GLP-1, GIP and glucagon). This comparison explains what that difference means in terms of mechanism and evidence.
Compare mechanism, class, receptors and evidence. All compounds are offered with ≥99% purity verified by HPLC and a batch COA.
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Class | Agonista GLP-1 (simple) | A dual GIP/GLP-1 agonist | Triple GLP-1/GIP/glucagon agonist |
| Receptors | GLP-1 | GIP + GLP-1 | GLP-1 + GIP + glucagon |
| Mecanismo distintivo | Glucose-dependent insulin, satiety and gastric emptying | Incretin co-activation: greater metabolic magnitude | Adds energy expenditure via glucagon |
| Vida media | ~1 week (C18 acylation) | ~1 semana (semanal) | Prolongada (semanal, fase temprana) |
| Trial programs | SUSTAIN, STEP, SELECT | SURPASS, SURMOUNT | Fase temprana |
| Maturity of the evidence | The most established | Consolidada | The most recent |
The conceptual axis is simple: more co-activated targets mobilize more metabolic levers. Semaglutide is the class reference and the one with the most established evidence. Tirzepatide, by adding the GIP receptor, shows in studies a greater metabolic magnitude than GLP-1 agonism alone. Retatrutide adds glucagon agonism —associated with greater energy expenditure— and represents the newest frontier, with early-phase data.
All three share the same profile of most frequent events: gastrointestinal discomfort (nausea, early satiety), consistent with slowed gastric emptying and typically dependent on titration speed.
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The number of receptors they activate: semaglutide agonizes only the GLP-1 receptor; tirzepatide is dual (GIP + GLP-1); and retatrutide is triple (GLP-1 + GIP + glucagon). The more receptors co-activated, the more metabolic pathways mobilized.
Glucagon receptor agonism is associated with greater energy expenditure and hepatic lipid mobilization, which add to the incretin effect of GLP-1 and GIP.
Semaglutide, with the SUSTAIN and STEP programs and cardiovascular data (SELECT). Tirzepatide has SURPASS and SURMOUNT; retatrutide is at an earlier stage.
Purity ≥99% verificada por HPLC and batch COA.
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