Retatrutide and Liraglutide are each a copy of the gut hormone GLP-1.
GLP-1 is what your gut releases after a meal to tell your brain you have eaten.
The difference is reach: Liraglutide acts on 1 receptor and Retatrutide acts on 3 receptors. More receptors has generally meant more effect, and more side effects.
| Comparison | Retatrutide LY3437943 · reta | Liraglutide Victoza · Saxenda |
|---|---|---|
| How it works | How it works Retatrutide adds a third target, glucagon, to the two tirzepatide already hits. Glucagon is the interesting one, because it does something the others do not. | How it works Liraglutide works on the same receptor as semaglutide. The difference is how long it lasts, which is why it is a daily injection rather than a weekly one. |
| What it is | An experimental weekly shot with some of the biggest weight-loss numbers yet in trials. | A daily version of the Ozempic-style shot for weight loss and blood sugar. |
| Status | In trialsInvestigational | FDA approvedFDA-approved |
| Typical dose | 1–12 mg per dose | 0.6–3 mg per day |
| How often | Weekly | Daily |
| Stays active | ~6 days | ~13 hours |
| Dose comes from | Clinical trial protocol | FDA drug label |
| Cycled? | Not cycled in the trials Clinical trial protocol | Not cycled FDA drug label |
| What it does | ||
| Drug class | GLP-1/GIP/glucagon agonist | GLP-1 agonist |
| Used for | People follow it for very large weight loss, around a quarter to nearly a third of body weight in trials. It acts on three appetite and metabolism pathways at once. | A daily version of the same appetite-lowering approach as Ozempic-style drugs, used for weight loss and blood sugar. It is older and a bit milder than the weekly options. |
| Receptors hit | GLP-1, GIP, glucagon | GLP-1 |
| Numbers | ||
| Full dose line | 1 up to 12 mg per dose (start low, increase slowly) | 0.6 up to 3 mg per day (start low, increase slowly) |
| Why that cycle | Given continuously for the whole study period: TRIUMPH-1, 80 weeks with an extension to 104. The dose is stepped up at the start, which is a ramp rather than a cycle, and no trial in this class built in a planned break. | A daily drug taken continuously. Weight returned after withdrawal in the trials. |
| Weight / effect | ~24% body weight lost | ~7% body weight lost |
| Chain length | 30 residues | 31 residues |
| Common vial | 10 mg | 18 mg |
| Before you start | ||
| Route | Under the skin (subcutaneous) | Under the skin (subcutaneous) |
| Do not use if | Not legally available outside clinical trials, so no prescriber is assessing whether it suits you Pregnancy, or trying to become pregnant | A personal or family history of medullary thyroid cancer, or the genetic condition MEN 2 Pregnancy, or trying to become pregnant A history of pancreatitis |
What separates them
Proof behind the dose. Liraglutide has a dose taken straight off an FDA drug label. Retatrutide has a dose from a clinical trial protocol.
What doesn't differ: They are both taken the same way (under the skin).
What people actually report
Retatrutide
- Stomach side effects like nausea and vomiting are the main issue.
- It must be increased slowly from a low dose over months, and it is not legally sold outside clinical trials.
- Severe stomach pain that spreads to your back
- Vomiting badly enough that you cannot keep fluids down
Liraglutide
- Nausea and stomach upset are common, worst early and when the dose goes up.
- It carries a warning about a rare thyroid tumor risk.
- Severe stomach pain that spreads to your back
- A lump or swelling in your neck, hoarseness, or trouble swallowing
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.