Triple GIP/GLP-1/glucagon agonist · Investigational
An investigational, not-yet-approved triple-action medication that produced the largest weight loss seen so far — up to ~25–30%.
✦ 2 min read · 2 sourcesWhat it is
Retatrutide is an experimental triple receptor agonist (GIP, GLP-1, and glucagon), developed by Eli Lilly. It is not FDA-approved for any use anywhere as of mid-2026 and is available only through clinical trials. Products sold online as 'retatrutide' are unapproved and not quality-controlled — this site endorses no seller.
How it works
It adds glucagon-receptor activation on top of the GIP and GLP-1 actions of tirzepatide. In this combination, glucagon is thought to increase energy expenditure and reduce liver fat, alongside the appetite effects of GIP and GLP-1.
What the evidence shows
In a Phase 2 trial, adults with obesity lost ~24% of body weight at 12 mg over 48 weeks. In 2026, the Phase 3 TRIUMPH-1 trial reported ~17.6% (4 mg), ~23.7% (9 mg), and ~25.0% (12 mg) over 80 weeks vs ~3.9% placebo — with up to ~30% in a higher-BMI subgroup that continued treatment. Long-term safety is still being established.
Quick check
Four questions, ~60 seconds, with a sourced result.
The honest take
Not FDA-approved — trials only
Status & safety
Investigational and not approved. The only legitimate, supervised access today is a clinical trial. A distinguishing effect (from glucagon activity) is a modest rise in resting heart rate. Do not buy or use unapproved 'research' versions; discuss approved options with a clinician.
Summaries of published, third-party research for educational purposes. Not medical advice; not a claim of efficacy or safety for any use.
New, plain-language summaries as the literature develops. Educational only — no products, nothing for sale.
GLP-1 receptor agonist · FDA-approved
A once-weekly, FDA-approved GLP-1 medication that helped adults lose roughly 15% of body weight on average in trials.
Read more →Dual GIP/GLP-1 agonist · FDA-approved
A once-weekly, FDA-approved dual-action medication — the largest average weight loss of the approved options, around 21%.
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