What did the retatrutide TRIUMPH-2 and TRIUMPH-3 trials show?

Both Phase 3 trials met their endpoints. TRIUMPH-2 (adults with type 2 diabetes and obesity or overweight) reported up to 20.8% mean body-weight reduction at 80 weeks on the 12 mg dose, with A1c falling by as much as 1.6%. TRIUMPH-3 (adults with severe obesity and established cardiovascular disease) reported up to 22.6% mean weight reduction at 80 weeks on 12 mg. Placebo groups lost roughly 3-4%.

How much weight did retatrutide produce in TRIUMPH-3?

In TRIUMPH-3, adults with severe obesity (BMI 35 or higher) and established cardiovascular disease lost an average of 21.6% of body weight on retatrutide 9 mg and 22.6% on 12 mg over 80 weeks, versus 3.2% on placebo - equivalent to roughly 52-56 lbs at the top doses.

What were the main side effects of retatrutide in the Phase 3 trials?

The most common adverse events were gastrointestinal and dose-related: diarrhea, nausea, constipation, decreased appetite and vomiting - the class-typical GLP-1 profile. Discontinuation due to adverse events ranged from 3.8% to 13.5% across retatrutide arms versus about 4.8-4.9% on placebo.

When will retatrutide be submitted to the FDA?

Eli Lilly has said it plans to submit a Biologics License Application (BLA) for retatrutide to the FDA in the first quarter of 2027. Approval, if granted, would follow FDA review of the full data package on its own timeline - so a launch is not expected before 2027-2028. Retatrutide remains investigational and unapproved in 2026.

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Retatrutide TRIUMPH-2 & TRIUMPH-3: Two More Positive Phase 3 Obesity Trials

Eli Lilly has reported positive topline results from two more Phase 3 trials of retatrutide (LY3437943), its triple GLP-1 / GIP / glucagon receptor agonist. The two readouts - TRIUMPH-2 and TRIUMPH-3 - deliver significant weight loss and, in the diabetes cohort, meaningful A1c reduction. Lilly now says retatrutide has cleared five positive Phase 3 studies and that it plans to file for FDA approval in the first quarter of 2027.

This is a research-focused walk-through of what the two trials measured and what they reported. RUO framing throughout: retatrutide is investigational, not approved, and supplied by us strictly as a research reagent (Retatrutide) - not for human consumption or weight-loss use.

The Headline Numbers

Trial Population Dose Mean weight loss (80 wks) TRIUMPH-2 T2D + obesity / overweight (n=1,152) 4 mg 12.7% (29.8 lbs) 9 mg 19.1% (45.4 lbs) 12 mg 20.8% (49.6 lbs) Placebo 4.0% (9.3 lbs) TRIUMPH-3 Severe obesity (BMI ≥35) + established CVD (n=1,949) 9 mg 21.6% (52.7 lbs) 12 mg 22.6% (55.8 lbs) Placebo 3.2% (7.7 lbs)

Both trials ran for 80 weeks . The percentages are mean body-weight change from baseline at the top of the dose range, with placebo groups losing roughly 3-4% - the usual lifestyle-intervention background seen across the GLP-1 category.

TRIUMPH-2: Weight Loss and Glucose Control

TRIUMPH-2 enrolled 1,152 adults with type 2 diabetes who were also living with obesity or overweight. It carried the harder dual test: historically, diabetes cohorts lose less weight on incretin drugs than non-diabetic cohorts, so the numbers here matter as a floor rather than a ceiling.

Weight: up to 20.8% mean reduction on 12 mg (about 49.6 lbs), 19.1% on 9 mg, 12.7% on 4 mg - versus 4.0% on placebo.

A1c: reductions of up to 1.6% (on the 9 mg arm), against just 0.2% on placebo. That is a clinically meaningful glucose-lowering effect on top of the weight result.

The dual weight-plus-A1c signal is the data Lilly needs to position retatrutide the way it positioned tirzepatide - one molecule underpinning both a diabetes label (Mounjaro) and an obesity label (Zepbound). For a mechanistic comparison of the two compounds, see retatrutide vs tirzepatide.

TRIUMPH-3: The High-Risk Cardiovascular Cohort

TRIUMPH-3 is the more striking of the two. It enrolled 1,949 adults with severe obesity (BMI ≥35) and established cardiovascular disease - a higher-risk, harder-to-treat population than a typical obesity trial. Even so:

22.6% mean weight loss on 12 mg (about 55.8 lbs) and 21.6% on 9 mg, versus 3.2% on placebo, at 80 weeks.

Producing north of 20% weight loss in patients who already have cardiovascular disease is the kind of result that drives the "metabolic therapy, not just weight-loss drug" narrative. It is not, however, a cardiovascular outcomes result: TRIUMPH-3 measured weight, not major adverse cardiovascular events (MACE). A dedicated CV-outcomes readout - the endpoint that earned semaglutide its SELECT indication - is a separate, multi-year question that sits later in the program (see our TRIUMPH program overview).

How It Stacks Up

For context, tirzepatide's SURMOUNT-1 reported ~20.9% at the top dose over 72 weeks in non-diabetic obesity, and semaglutide's STEP-1 reported ~14.9%. Retatrutide's earlier Phase 2 obesity data reached ~24.2% at 48 weeks. The new figures - 20.8% in a diabetes cohort and 22.6% in a high-CV-risk cohort - land in the upper band of the category, and they do so in populations that usually blunt the numbers. The full percentage breakdown and honest caveats are in retatrutide weight-loss percentage results.

The Safety Picture

The adverse-event profile was class-typical and dose-related . The most common events were gastrointestinal:

Diarrhea, nausea, constipation, decreased appetite and vomiting - the familiar GLP-1 tolerability signature.

Discontinuation due to adverse events ranged 3.8%-13.5% across the retatrutide arms, versus about 4.8%-4.9% on placebo. The high end of that range tracks the higher doses, which is the trade-off buried under every headline weight-loss number: the biggest results come from the doses the most people struggle to stay on.

For a fuller read on the safety literature and why self-sourcing is the real risk, see is retatrutide safe?

Status check. Retatrutide remains investigational and unapproved in 2026. A positive Phase 3 readout is a regulatory pre-requisite, not a clearance. Eli Lilly has stated it plans a BLA submission in Q1 2027; any approval and launch would follow FDA review on its own timeline. Nothing here is medical advice, dosing guidance, or a directive to use the compound. New-U supplies retatrutide as a research reagent (Retatrutide) for laboratory use only - not for human consumption or weight-loss application.

What Happens Next

BLA filing, Q1 2027. With five positive Phase 3 studies in hand, Lilly's stated plan is an FDA submission in the first quarter of 2027. The earliest realistic approval window is 2027/28.

Full data at a congress / in a journal. Topline press-release numbers precede the peer-reviewed detail - discontinuation curves, responder rates (% hitting ≥15%, ≥20%, ≥25% loss) and subgroup breakdowns are what the research community will scrutinise.

The cardiovascular-outcomes question. TRIUMPH-3 showed weight loss in CV patients; it did not test MACE. Whether retatrutide earns a cardiovascular outcomes label is the next-order question.

Dose-tolerability at scale. The 12 mg arm carries both the best weight numbers and the highest discontinuation - real-world persistence will decide how much of the trial effect survives outside a trial.

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Retatrutide TRIUMPH-2 & TRIUMPH-3: Two More Positive Phase 3 Obesity Trials

The Headline Numbers

TRIUMPH-2: Weight Loss and Glucose Control

TRIUMPH-3: The High-Risk Cardiovascular Cohort

How It Stacks Up

The Safety Picture

What Happens Next

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