Side effects guide

Retatrutide Side Effects

GLP-1 / GIP / Glucagon

In the Phase 2 obesity trial, the most common adverse events were gastrointestinal: nausea, diarrhea, vomiting, and constipation. They were generally mild to moderate and tended to track the dose, showing up most during escalation.[1]

Reviewed for accuracy · Last reviewed July 7, 2026

Reported side effects

COMMONNausea · Reduced appetite · Constipation · Injection-site irritation
LESS COMMONFatigue · Dizziness · Gallbladder issues

Because retatrutide is investigational, its longer-term safety profile in humans is not yet well characterized, and there is no approved label documenting rarer risks. The hedged reading is that the short-term trial data looks similar in character to other incretin peptides, but the evidence base is far smaller.

Seek medical attention ifYou notice severe abdominal pain, signs of an allergic reaction, or persistent vomiting.

Managing side effects

Many people find gastrointestinal effects ease as the body adjusts to a dose. Injecting after a lighter meal and holding a dose steady before the next step-up are commonly discussed ways to limit nausea.

FAQ

How common are side effects with retatrutide?In the Phase 2 trial gastrointestinal effects were the most frequent adverse events, mostly mild to moderate and dose-related. Rarer or long-term risks are not yet well characterized in humans.
Do the side effects get better over time?Trial data suggests gastrointestinal effects were concentrated around dose increases, and they often settle as the body adjusts, though individual experience varies.

References

  1. Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 TrialNew England Journal of Medicine · 2023 · PMID 37366315 · DOI 10.1056/NEJMoa2301972
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This page is an independent educational reference and is not medical advice, and does not indicate any approval status for any use. Talk to a doctor before starting any compound.