Retatrutide is an investigational triple-receptor (GIP/GLP-1/glucagon) agonist in late-stage trials for weight management and type 2 diabetes. Phase 3 data (TRIUMPH-1) has reported substantial average weight loss, but as of 2026 it is not FDA-approved or available by prescription.
Not yet FDA-approved
Retatrutide is still in Phase 3 trials (Eli Lilly's TRIUMPH program), with FDA submission not expected until Q1 2027. The Phase 2 trial below is peer-reviewed and independently verified. The more dramatic Phase 3 numbers circulating (up to ~30% weight loss) are from Lilly's own press releases — real, but not yet peer-reviewed publications.
Benefits
Retatrutide is a triple hormone receptor agonist — activating GIP, GLP-1, and glucagon receptors in one molecule. The added glucagon-receptor activity (beyond tirzepatide's GIP/GLP-1 pair) is the proposed basis for its larger reported weight-loss effect.
Phase 2, obesity (peer-reviewed, n=338, 48 weeks): body weight reduction of 17.1% (4mg), 22.8% (8mg), and 24.2% (12mg) vs. 2.1% for placebo. At the 12mg dose, 93% of participants achieved ≥10% weight loss. Jastreboff et al., N Engl J Med, 2023
Phase 3 (press release, not yet peer-reviewed): Lilly's TRIUMPH-1 topline results (n=2,339) reported up to ~30% mean weight loss at higher doses over 80-104 weeks.
Dosage
Phase 2 (peer-reviewed): once-weekly subcutaneous 1mg, 4mg, 8mg, or 12mg, with a lower starting dose used to reduce GI side effects. No FDA-labeled dose exists yet since this compound isn't approved.
Side Effects
GI events (nausea, vomiting, diarrhea, constipation) were the most common adverse events, dose-related and mostly mild to moderate. Heart rate showed dose-dependent increases, peaking around week 24, declining afterward. Dysesthesia (tingling/altered sensation) has been reported at a meaningful rate in Phase 3 data, linked to the drug's glucagon-receptor activity — a side effect profile point that distinguishes it from GLP-1/GIP-only drugs like tirzepatide.
Results Timeline
Phase 2: measured at 24 and 48 weeks. Phase 3 (press release): 80-104 week data being reported through the TRIUMPH program.
Is Retatrutide FDA-approved?+
No, not as of 2026. Eli Lilly has the primary efficacy dataset for a filing, expected before the end of 2026, but a filing is not an approval.
How much weight loss has Retatrutide shown in trials?+
In the TRIUMPH-1 trial, the 12mg group averaged 28.3% weight loss at 80 weeks, with 45.3% of that group losing 30% or more of body weight.
Is Retatrutide the same as Tirzepatide?+
No. Tirzepatide targets two receptors (GIP/GLP-1) and is FDA-approved as Mounjaro/Zepbound; Retatrutide targets a third (glucagon) receptor as well and remains investigational.
Looking for something specific, or placing a wholesale order? Send us a DM or email.