GLP-1 Peptides Compared: Semaglutide, Tirzepatide & Retatrutide
Semaglutide, tirzepatide and retatrutide are compared here by receptor profile: GLP-1 alone, GIP plus GLP-1, or GIP plus GLP-1 plus glucagon. The overview explains this distinction for controlled laboratory questions without claiming suitability or superiority.
One, Two, or Three Receptors — the Principle
All three peptides belong to the GLP-1 agonist family, but they differ in how many docking stations (receptors) they serve at once. Think of it as a ladder: semaglutide serves one receptor (GLP-1), tirzepatide two (GIP + GLP-1), retatrutide three (GIP + GLP-1 + glucagon). Each rung adds one more signaling pathway.
For research this means: a single receptor can be studied cleanly in isolation, several receptors yield a broader but more complex activity profile. Which rung is the right one depends solely on the research question — not on which peptide is "stronger".
Semaglutide — One Receptor (GLP-1)
Semaglutide is the pure GLP-1 agonist and the reference molecule of the class — the most thoroughly studied peptide of this group (STEP and SUSTAIN series). It is the clean tool for studying exactly one signaling pathway in isolation.
Details in the article Semaglutide or in the direct comparison Tirzepatide vs. Semaglutide.
Tirzepatide — Two Receptors (GIP + GLP-1)
Tirzepatide has agonist activity at GIP and GLP-1 receptors. This dual receptor profile differs from selective GLP-1 receptor agonists; clinical programmes such as SURPASS and SURMOUNT concern medicine research and do not establish the quality of a shop batch.
Available as Glowjaro. Details in the article Tirzepatide or in the comparison Retatrutide vs. Tirzepatide.
Retatrutide — Three Receptors (GIP + GLP-1 + Glucagon)
Retatrutide is the triple GIP/GLP-1/glucagon agonist — the newest and most experimental of the three. The additional glucagon pathway makes it the broadest multi-receptor tool of the group.
Available as Glowreta. Details in the article Retatrutide or in the comparison Retatrutide vs. Semaglutide.
Which GLP-1 Peptide for Which Research?
Selection for a laboratory design depends on the research question: semaglutide targets the GLP-1 receptor, tirzepatide GIP and GLP-1, and retatrutide additionally the glucagon receptor. This is not a claim of suitability, safety or superiority. Published analytical reports apply only to the specifically identified sample or batch.
FAQ: GLP-1 Peptides Compared
Which GLP-1 peptides are there?
This page compares semaglutide as a GLP-1 receptor agonist, tirzepatide as a GIP/GLP-1 receptor agonist and retatrutide as a GIP/GLP-1/glucagon receptor agonist. This is a comparison of research compounds, not a complete list of all GLP-1-related research compounds.
What do single, dual, and triple agonist mean?
The number indicates how many receptor classes a peptide addresses at once. More receptors mean a broader but less isolatable activity profile.
Are GLP-1 research peptides intended for human use?
No. All are offered exclusively for laboratory research and are not approved as medicines for human use.
Sources
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989–1002. 10.1056/NEJMoa2032183
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205–216. 10.1056/NEJMoa2206038
- Frías JP, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021;385(6):503–515. 10.1056/NEJMoa2107519
- Jastreboff AM, et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514–526. 10.1056/NEJMoa2301972
The studies cited refer to the clinical research status of the respective compounds and serve scientific context only. They do not constitute any statement about our research products, which are intended for laboratory research exclusively.
Disclaimer: This article provides context for published research. Semaglutide is not part of our product range. All information presented in this article is based on published research findings and does not constitute medical claims or therapeutic promises. The study programs mentioned (STEP, SUSTAIN, SURPASS, SURMOUNT, TRIUMPH) are referenced solely to contextualize the current state of scientific research.