Retatrutide vs Semaglutide vs Tirzepatide: What’s Different
The one-line answer
Semaglutide and tirzepatide are FDA-approved drugs. Retatrutide is not approved anywhere and remains an investigational compound in clinical trials. That single difference in regulatory status is the most important thing to understand before comparing anything else about the three.
Approval status and brand names
| Compound | Status | Approved brand names | Developer |
|---|---|---|---|
| Semaglutide | FDA-approved | Ozempic (Dec 2017), Wegovy (Jun 2021) | Novo Nordisk |
| Tirzepatide | FDA-approved | Mounjaro (May 2022), Zepbound (Nov 2023) | Eli Lilly |
| Retatrutide | Investigational, not approved | None yet; Lilly plans to file for approval in Q1 2027 | Eli Lilly |
The approval dates above come from FDA records. See our full breakdown of retatrutide’s FDA timeline for how the 2027 filing plan came about.
Same company, different molecules
Retatrutide and tirzepatide are both developed by Eli Lilly, which is why they are sometimes confused with each other. They are not the same compound. Tirzepatide has been through the full approval process twice, once as Mounjaro and once as Zepbound, each for a different indication. Retatrutide has not completed that process for either indication or any other use. Semaglutide, despite being grouped with the other two in casual conversation, comes from a different company, Novo Nordisk, with its own separate development and approval history.
Why people search for all three together
Retatrutide, semaglutide and tirzepatide are frequently discussed together because they come from the same broad category of injectable peptide compounds studied for metabolic research, and because Lilly’s trial results for retatrutide have drawn comparisons to its own approved drug, tirzepatide. That comparison is a media and investor talking point about drug development, not a statement that the three are interchangeable or equally available. Two are approved prescription medicines. One is not approved for any use.
What this means for research use
Peptryn sells retatrutide as a laboratory research material only, the same way it sells every other compound in its catalog. Nothing about Lilly’s own development timeline for the approved or investigational versions of these compounds changes that. We do not sell semaglutide or tirzepatide, and we do not give dosing or administration guidance for anything we sell. See our retatrutide product page for lot COAs, and our guide to peptide legality for how research-use sales are treated.
Common questions
Is retatrutide a stronger version of tirzepatide?
That is a claim about therapeutic effect, and Peptryn does not make effect claims about any compound it sells. What can be stated factually is that retatrutide has not completed FDA review for any use, while tirzepatide has been approved twice, for two different indications.
Will retatrutide be sold under a brand name once approved, like Ozempic or Mounjaro?
Lilly has not announced a brand name for retatrutide as of this writing. Brand names are typically assigned closer to or at the time of FDA approval.
Can I buy semaglutide or tirzepatide from Peptryn?
No. Peptryn’s catalog does not include semaglutide or tirzepatide. See our retatrutide listing for the compound we do sell, supplied strictly for laboratory research.
Related: Retatrutide’s FDA approval status · Retatrutide’s half-life · Buying retatrutide for research · Popular peptides
For laboratory research use only. Not for human or veterinary use, and not a drug, food, dietary supplement or cosmetic. You must be 21 or older to buy.
