Retatrutide

Retatrutide is an investigational injectable that activates three receptors at once: GLP-1, GIP and glucagon. It is not approved by FDA for any use, and it is not available by prescription in the United States. Everything below comes from trial data, not from a label.

The phase 2 results are why it gets so much attention. Published in 2023, the trial enrolled 338 adults with obesity. At 48 weeks, average weight change was −8.7% at 1 mg, −17.1% at 4 mg, −22.8% at 8 mg and −24.2% at 12 mg, against −2.1% on placebo. At the 12 mg dose, 93% of participants lost at least 10% of body weight and 83% lost at least 15%. Those are the largest figures published for a pharmacological weight treatment to date.

They also come with the usual caveats of an early trial. Phase 2 is smaller and shorter than phase 3, gastrointestinal adverse events were dose-related, and the trial recorded dose-dependent increases in heart rate that peaked at 24 weeks before declining. Phase 3 programs regularly produce smaller effects than phase 2 suggested.

The part that matters most for safety is regulatory, not clinical. FDA states plainly that retatrutide cannot be used in compounding under federal law, that it is not a component of any FDA-approved drug, and that it has not been found safe and effective for any condition. The agency has warned telehealth companies for marketing it, ingredient distributors for selling it to compounders, and outsourcing facilities for repackaging it. Anything sold online as retatrutide is outside the legal supply chain entirely.

If a provider offers you retatrutide today, the right question is what exactly they are selling and under what authority. Our retatrutide evidence review and mechanism comparison cover the trial record and the marketing around it.