RetatrutideDosage, Side Effects & Legal Status
Retatrutide has striking Phase 2 obesity results, but it remains an investigational medicine. The evidence people cite comes from a 338-person, 48-week randomized trial, not from the unregulated products marketed under its name.
Reviewed by the PepGuard team · Last reviewed Jul 28, 2026
Investigational triple agonist targeting GIP, GLP-1, and glucagon receptors · also sold as LY3437943, triple GIP, GLP-1, and glucagon receptor agonist
Photo: Alexander Mass / UnsplashThe studies behind the headline.
Results are reported as published. A result in one population does not establish a benefit in another.
| Study | Population | Observed result | Limit |
|---|---|---|---|
| Jastreboff et al., NEJM Phase 2 | 338 adults with obesity or overweight plus a weight-related condition | At 48 weeks, mean body-weight change was -24.2% with 12 mg retatrutide versus -2.1% with placebo. | The result is from a Phase 2 trial and does not verify products sold outside the trial. |
| Jastreboff et al., response thresholds | Participants in the same Phase 2 trial | At 48 weeks, 83% of the 12 mg group reached at least 15% weight reduction, versus 2% with placebo. | This is a trial endpoint, not a forecast for an individual or a substitute for longer-term outcome data. |
Retatrutide is not a cagrilintide stack
Retatrutide is a triple agonist, while cagrilintide is an amylin analogue. The published trials evaluate them as separate investigational products, not as a combined self-treatment.
Read the cagrilintide evidence reportWhat the literature and self-reports actually say.
| What's cited | Range |
|---|---|
| Phase 2 trial dose levels | 1, 4, 8, or 12 mg, subcutaneous, once weekly |
| Starting-dose comparison in higher-dose arms | 2 mg or 4 mg, studied before escalation |
| Human dose for non-trial retatrutide | Not established |
Published dose levels describe research arms. They are not an instruction to start, titrate, reconstitute, or combine retatrutide. The study itself found that gastrointestinal adverse events varied by dose and that a lower starting dose partly reduced them.
Signal strength, not just a list.
How often each effect shows up in the available sources, and how solid that evidence actually is.
| Signal | Frequency | Context |
|---|---|---|
| Gastrointestinal adverse events | commonly reported | The Phase 2 trial described these as the most common adverse events; they were dose-related and mostly mild to moderate. |
| Increased heart rate | occasionally reported | The trial reported dose-dependent increases that peaked at 24 weeks and declined afterward. |
| Long-term cardiovascular and real-world safety | unknown / not studied | Phase 2 follow-up was 48 weeks and cannot answer every longer-term safety question. |
Not FDA-approved for weight loss or any other indication in the US.
Retatrutide was evaluated in randomized trials as an Eli Lilly investigational product. A published Phase 2 result is not an approval, and it does not establish the identity, purity, dose, or safety of material sold outside a regulated clinical program.
Every claim above, traced back.
Primary studies, reviews, regulatory pages, and trial registries. Click through and check them yourself.
Retatrutide questions, answered.
No. Retatrutide is an investigational medicine. Published trial results and internet listings do not make a product FDA-approved or establish that a vial contains the trial compound.
The trial tested once-weekly 1, 4, 8, and 12 mg arms for 48 weeks, with different starting doses in some higher-dose groups. Those are study arms, not a dosing recommendation.
In 338 adults with obesity, mean weight change at 48 weeks was -24.2% in the 12 mg group versus -2.1% with placebo. The most common adverse events were gastrointestinal and were dose-related.
Keep researching.
This is a preview of the Retatrutide report.
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