Semaglutide vs Tirzepatide vs Retatrutide
Semaglutide, Tirzepatide, and Retatrutide represent three generations of incretin-based peptides studied in metabolic research, distinguished primarily by how many receptor pathways each engages. Semaglutide is characterized as a single GLP-1 receptor agonist, Tirzepatide as a dual GIP/GLP-1 agonist, and Retatrutide as a triple GLP-1/GIP/glucagon agonist. This progression from one to three receptor targets is one of the most actively discussed trends in the research literature on metabolic peptides.
| Property | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Receptor targets | GLP-1 | GIP + GLP-1 | GLP-1 + GIP + glucagon |
| Class | Single agonist | Dual agonist | Triple agonist |
| Research code | — | LY3298176 | LY3437943 |
| Primary research focus | Glucose-dependent insulin signaling, gastric motility | Combined incretin signaling | Multi-pathway metabolic signaling incl. energy expenditure |
| Distinguishing feature | Most-established of the three | Adds GIP pathway | Adds glucagon pathway |
| Research maturity | Largest body of literature | Substantial | Newest, smaller literature |
Semaglutide (GLP-1)
Semaglutide is characterized in research as a single GLP-1 receptor agonist and has the largest body of published literature of the three. The GLP-1 pathway is associated in preclinical models with glucose-dependent insulin signaling and gastric motility. As the most-established compound in the incretin class, it is frequently used as the reference point against which dual and triple agonists are compared. In our catalog it is listed as GLP-1 SM.
Tirzepatide (GIP + GLP-1) and Retatrutide (GLP-1 + GIP + glucagon)
Tirzepatide is characterized as a dual agonist, engaging both the GIP and GLP-1 receptors. Research literature examines whether combined incretin signaling produces outcomes distinct from single-pathway GLP-1 activity. In our catalog it is listed as GLP-1 TZ.
Retatrutide extends this further as a triple agonist, adding glucagon receptor activity to the GIP/GLP-1 profile. The glucagon pathway is studied in connection with hepatic glucose output and energy expenditure, and its inclusion is the defining feature of the triple-agonist research profile. In our catalog it is listed as GLP-3 RT. For a deeper look, see our Retatrutide overview.
How Researchers Distinguish Them
The three compounds are most simply grouped by receptor count: one (Semaglutide), two (Tirzepatide), three (Retatrutide). Research selecting among them typically depends on which pathway or combination of pathways a study is designed to investigate. Semaglutide offers the deepest existing literature for GLP-1-focused work; Tirzepatide adds the GIP dimension; Retatrutide adds glucagon for multi-pathway studies. Because Retatrutide is the newest, its literature is smaller and it is often studied comparatively against the other two rather than in isolation.
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Frequently Asked Questions
What is the main difference between the three?
The number of receptor pathways engaged: Semaglutide (GLP-1 only), Tirzepatide (GIP + GLP-1), Retatrutide (GLP-1 + GIP + glucagon).
Which has the most research behind it?
Semaglutide has the largest body of published literature; Retatrutide is the newest with the smallest.
Are these FDA approved?
No. All are research peptides sold strictly for in-vitro study and not approved for human consumption.