Study profile

Retatrutide: phase 2 and phase 3 evidence

Investigational triple GIP / GLP-1 / glucagon receptor agonist. Not FDA-approved as of the October 2026 content review. Content review 2026-10-11.

Group averages from separate trials with different populations — not individual predictions and not head-to-head comparisons. Only physician-verified records (phase 2 and TRIUMPH-1) feed the calculator. TRIUMPH-2 and TRIUMPH-3 are shown for reference only and are pending physician review. RetaRevolution is not affiliated with Eli Lilly and does not sell or source retatrutide.

Phase 2 obesity trial

Physician-verified · Avi Shaw, MD, 2026-10-11

12 mg · wk 24-17.5%

Placebo · wk 24-1.6%

12 mg · wk 48-24.2%

Placebo · wk 48-2.1%

ClinicalTrials.gov: NCT04881760
Population: Adults 18–75 years without type 1 or type 2 diabetes, with BMI ≥30 kg/m², or BMI 27 to <30 kg/m² plus at least one weight-related condition (registry lists hypertension, dyslipidemia, cardiovascular disease). 51.8% men (NEJM).
Sample size: 338
Doses: Once-weekly subcutaneous retatrutide (LY3437943) vs placebo, randomized 2:1:1:1:1:2:2 (placebo : 1 mg : 4 mg [start 2 mg] : 4 mg [start 4 mg] : 8 mg [start 2 mg] : 8 mg [start 4 mg] : 12 mg [start 2 mg]), escalation completed by week 12, for 48 weeks.
Duration: 48 weeks
Primary endpoint: Percentage change in body weight from baseline to week 24. Secondary: percentage change to week 48; proportions achieving ≥5%, ≥10%, ≥15% weight reduction.
Safety: Most common adverse events were gastrointestinal, dose-related, mostly mild to moderate, and partly mitigated by a 2 mg vs 4 mg starting dose (NEJM).
Dose-dependent heart-rate increases peaked at week 24 and then declined (NEJM).
Serious adverse events through week 52 (registry): placebo 3, 1 mg 3, 4 mg [start 2 mg] 0, 4 mg [start 4 mg] 2, 8 mg [start 2 mg] 1, 8 mg [start 4 mg] 2, 12 mg 2.
One death in the 4 mg (start 4 mg) arm; neither source accessed states that the death was caused by the drug.
Limitations: Phase 2 dose-finding trial with a modest sample (338 participants), split across seven arms; per-arm estimates are less precise than in phase 3 trials.
48-week treatment period; durability of weight loss and long-term safety beyond 48 weeks (safety follow-up to 52 weeks) were not assessed.
Not powered for cardiovascular, mortality, or other clinical outcomes.
Excluded people with type 1 or type 2 diabetes and those outside 18–75 years; results may not apply to these groups.
Efficacy analysis excluded data after study-drug discontinuation, which may overstate effects compared with a treatment-policy analysis.
Investigational drug; findings require confirmation in ongoing phase 3 trials.
Citation: Jastreboff AM, Kaplan LM, Frías JP, Wu Q, Du Y, Gurbuz S, Coskun T, Haupt A, Milicevic Z, Hartman ML; Retatrutide Phase 2 Obesity Trial Investigators. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. doi:10.1056/NEJMoa2301972. Epub 2023 Jun 26. PMID: 37366315.

Phase 3 · TRIUMPH-1

Physician-verified · Avi Shaw, MD, 2026-10-11

12 mg · wk 80-25.0%

Placebo · wk 80-3.9%

ClinicalTrials.gov: NCT05929066
Population: Adults with obesity without diabetes (registry: BMI ≥30, or ≥27 with hypertension, dyslipidemia, obstructive sleep apnea or cardiovascular disease); subgroups of 574 with knee osteoarthritis and 243 with obstructive sleep apnea.
Sample size: 2339
Doses: Once-weekly subcutaneous retatrutide 4 mg, 9 mg or 12 mg vs placebo for 80 weeks. Calculator uses the 12 mg arm.
Duration: 80 weeks
Primary endpoint: Percent change in body weight (9 mg and 12 mg each vs placebo); WOMAC pain score in the knee osteoarthritis subgroup; apnea–hypopnea index in the sleep apnea subgroup.
Safety: Most common adverse events were gastrointestinal (NEJM abstract; full safety tables not yet reviewed).
Limitations: Results are group averages from adults without diabetes; they may not apply to people with diabetes or other populations.
Only the 80-week timepoint is published in the abstract; no 52-week figure is reported.
Safety detail is limited to the abstract; full-paper safety tables were not reviewed.
Sponsor-funded trial (Eli Lilly).
Investigational drug; not FDA-approved.
Citation: Jastreboff AM, Kaplan LM, Davies MJ, Wilding JPH, Ahmad NN, Murray M, Du Y, Makarova N, Giblin K, Schloot NC, Wang Y; TRIUMPH-1 Investigators. Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. N Engl J Med. 2026 Sep 29. doi:10.1056/NEJMoa2604169. Online ahead of print. PMID: 42814954.

Questions about these trials? See the Retatrutide FAQ or follow enrollment, results and news in the TRIUMPH trial tracker.

Phase 3 · TRIUMPH program

More phase 3 trials

Registry data retrieved 2026-10-11. Results so far come only from sponsor announcements, so no figures are shown until a peer-reviewed source is physician-verified.

TRIUMPH-2

Topline press release only — not peer-reviewed

Evidence under physician review

Weight-loss results, adverse events and limitations will appear after physician verification against a peer-reviewed publication.

ClinicalTrials.gov: NCT05929079
Registry status: Completed · 1,152 enrolled (actual)
Sponsor announcement: Read the source (not peer-reviewed)

TRIUMPH-3

Topline press release only — not peer-reviewed

Evidence under physician review

Weight-loss results, adverse events and limitations will appear after physician verification against a peer-reviewed publication.

ClinicalTrials.gov: NCT05882045
Registry status: Completed · 1,946 enrolled (actual)
Sponsor announcement: Read the source (not peer-reviewed)