Retatrutide Statistics & Trial Data (2026)

Investigational · not FDA approvedEditorially reviewed · Last updated 2026-07-02

Every published retatrutide efficacy and safety figure, pulled from the Phase 2 and Phase 3 readouts, with a primary source on every number. Free to quote and embed.

−28.3%
Average weight loss, 12 mg at 80 weeks (TRIUMPH-1)
Evidence: Phase 3 RCTSource
2,339
Participants randomized in the pivotal Phase 3 trial (TRIUMPH-1)
Evidence: EstimateSource
45.3%
Participants losing ≥30% of body weight, 12 mg at 80 weeks
Evidence: Phase 3 RCTSource
−24.2%
Average weight loss, 12 mg at 48 weeks (Phase 2, NEJM 2023)
Evidence: Phase 2Source
Evidence strength — how solid the data behind each labelled claim is, strongest to weakest: Evidence: Phase 3 RCTEvidence: Phase 2Evidence: Phase 1 PKEvidence: PreclinicalEvidence: Community-reportedEvidence: Estimate
Cite these statistics
“In Lilly's pivotal Phase 3 trial (TRIUMPH-1), retatrutide drove an average 28.3% body-weight loss at 80 weeks on the 12 mg dose — the largest weight loss reported for the drug to date.”
GLP-3 Wiki · https://glp3.wiki/statistics?utm_source=citation&utm_medium=copy&utm_content=cite#cite

Pastes with a live link in most editors.

Weight loss by dose (TRIUMPH-1, 80 weeks)

In TRIUMPH-1, retatrutide produced average weight loss of 19.0% at 4 mg, 25.9% at 9 mg, and 28.3% at 12 mg — versus 2.2% on placebo — at 80 weeks.
Weight loss by dose (TRIUMPH-1, 80 weeks)08152330−19.0%4 mg−25.9%9 mg−28.3%12 mg−2.2%Placebo% change
Weight loss by dose (TRIUMPH-1, 80 weeks) — data table
MetricValueSource
4 mg−19.0%[1]
9 mg−25.9%[1]
12 mg−28.3%[1]
Placebo−2.2%[1]

Phase 3, n=2,339 randomized, 80-week primary endpoint. The 12 mg arm averaged −70.3 lbs (−31.9 kg). Figures are the efficacy (on-treatment) estimand; the more conservative treatment-regimen estimand for 12 mg was −25.0% (−62.1 lbs).

Source: Eli Lilly and Company [1]

Read more: Retatrutide dosage guide · Dose calculator

The response deepens over time (12 mg)

On the 12 mg dose, average weight loss was 28.3% at 80 weeks. In a pre-specified extension of participants who began with a BMI of 35 or higher, those who continued to 104 weeks lost an average of 30.3% (−85.0 lbs) — still losing weight at the last measurement.
The response deepens over time (12 mg)02040Baseline−28.3%80 weeks (full 12 mg arm)−30.3%104 weeks (BMI ≥35 extension subgroup)
The response deepens over time (12 mg) — data table
MetricValueSource
80 weeks (full 12 mg arm)−28.3%[1]
104 weeks (BMI ≥35 extension subgroup)−30.3%[1]

The 80-week 28.3% is the full 12 mg arm. The 104-week 30.3% (−85.0 lbs / −38.5 kg) is a pre-specified blinded extension of the baseline-BMI-≥35 subgroup (~532 participants) — not the whole arm. Efficacy estimand.

Source: Eli Lilly and Company [1]

Read more: Retatrutide dosage guide · Dose calculator

How many hit each weight-loss milestone

In the Phase 2 obesity trial, 12 mg retatrutide got 100% of participants to ≥5% weight loss, 93% to ≥10%, and 83% to ≥15% — and in Phase 3 TRIUMPH-1, 45.3% reached ≥30%.
How many hit each weight-loss milestone≥5% weight loss100%≥10% weight loss93%≥15% weight loss83%≥30% weight loss (TRIUMPH-1)45.3%
How many hit each weight-loss milestone — data table
MetricValueSource
≥5% weight loss100%[3]
≥10% weight loss93%[3]
≥15% weight loss83%[3]
≥30% weight loss (TRIUMPH-1)45.3%[1]

The ≥5/≥10/≥15% thresholds are Phase 2 obesity (NEJM 2023, 12 mg from a 2 mg escalation); the ≥30% figure is Phase 3 TRIUMPH-1 at 80 weeks. Cross-trial — populations and durations differ.

Sources: New England Journal of Medicine [3] · Eli Lilly and Company [1]

Read more: Retatrutide dosage guide · Dose calculator

How retatrutide compares to approved drugs

Retatrutide's 28.3% weight loss (TRIUMPH-1) exceeds tirzepatide's 22.5% (SURMOUNT-1) and semaglutide's 14.9% (STEP 1) — across the three generations of GLP agonists, though cross-trial comparisons have real limits.
How retatrutide compares to approved drugs
Drug & trialWeight loss
Retatrutide 12 mg — TRIUMPH-1, 80 wks
−28.3%
Tirzepatide 15 mg — SURMOUNT-1, 72 wks
−22.5%
Semaglutide 2.4 mg — STEP 1, 68 wks
−14.9%

Cross-trial comparison — populations, durations, designs, AND statistical estimands differ. Each is the highest-dose result from that drug's pivotal general-obesity trial. Retatrutide and tirzepatide figures are efficacy estimands; semaglutide's −14.9% is the treatment-policy estimand (its efficacy estimand was −16.9%).

Sources: Eli Lilly and Company [1] · New England Journal of Medicine [4] · New England Journal of Medicine [5]

Read more: Retatrutide vs Mounjaro vs Ozempic

Development & readout timeline

Retatrutide's Phase 3 readouts landed in sequence: TRIUMPH-4 (Dec 2025), TRANSCEND-T2D-1 (Mar 2026), and the pivotal TRIUMPH-1 (May 2026).
  1. 2023
    Phase 2 obesity readout (NEJM)
  2. Dec 2025
    TRIUMPH-4 (knee osteoarthritis) readout
  3. Mar 19, 2026
    TRANSCEND-T2D-1 (type 2 diabetes) readout
  4. May 21, 2026
    TRIUMPH-1 (pivotal obesity) topline
~5,800
Total Phase 3 program enrolment
2,339
TRIUMPH-1 participants randomized
Development & readout timeline — data table
MetricValueSource
Phase 2 obesity readout (NEJM)2023[3]
TRIUMPH-4 (knee osteoarthritis) readoutDec 2025[6]
TRANSCEND-T2D-1 (type 2 diabetes) readoutMar 19, 2026[7]
TRIUMPH-1 (pivotal obesity) toplineMay 21, 2026[1]
Total Phase 3 program enrolment~5,800[8]
TRIUMPH-1 participants randomized2,339[2]

Program-wide enrolment (~5,800) is across the four core TRIUMPH weight-management trials, per the published TRIUMPH design paper. Retatrutide remains investigational — no FDA filing or approval date has been confirmed by Lilly or the FDA.

Sources: New England Journal of Medicine [3] · Eli Lilly and Company [6] · Eli Lilly and Company (via PR Newswire) [7] · Eli Lilly and Company [1] · TRIUMPH program design publication (PubMed) [8] · ClinicalTrials.gov [2]

Read more: FDA approval timeline

Safety signals by dose

In TRIUMPH-4, dysesthesia (abnormal skin sensation) affected 20.9% of the 12 mg arm versus 8.8% at 9 mg, and discontinuation for adverse events was 18.2% at 12 mg versus 12.2% at 9 mg.
Safety signals by dose01325385020.9%Dysesthesia, 12 mg8.8%Dysesthesia, 9 mg18.2%Discontinuation (AEs), 12 mg12.2%Discontinuation (AEs), 9 mg43.2%Nausea, 12 mg (TRIUMPH-4)% change
Safety signals by dose — data table
MetricValueSource
Dysesthesia, 12 mg20.9%[6]
Dysesthesia, 9 mg8.8%[6]
Discontinuation (AEs), 12 mg18.2%[6]
Discontinuation (AEs), 9 mg12.2%[6]
Nausea, 12 mg (TRIUMPH-4)43.2%[6]

Dysesthesia, discontinuation and nausea rates are all from TRIUMPH-4 (knee osteoarthritis). Nausea was 43.2% at 12 mg versus 10.7% on placebo. All gastrointestinal events were mostly mild-to-moderate and clustered during dose escalation.

Source: Eli Lilly and Company [6]

Read more: Side effects & safety

What we don't know yet
  • Long-term cardiovascular and renal safety — the TRIUMPH-5 outcomes trial (MACE endpoints) is multi-year and still accumulating.
  • Whether the dysesthesia signal persists or resolves with continued dosing — it emerged as a new, dose-dependent event and is being watched across readouts.
  • Head-to-head safety versus tirzepatide and semaglutide — no direct comparative trial has reported.
  • Real-world adherence and long-term weight maintenance after stopping — TRIUMPH-6 (weight maintenance) has not read out.

How we compile these statistics

  • Every figure links to its primary source — a peer-reviewed publication, a Lilly press release, or a trial registry record.
  • Dose-bearing numbers (efficacy by dose, adverse-event rates, titration) are human-checked against the source before publishing, because a wrong dose is real-world harm.
  • This is a founder-owned editorial compilation of published data — not clinical advice, and not affiliated with any manufacturer.
  • Cross-trial figures (e.g. retatrutide vs semaglutide vs tirzepatide) come from separate trials with different populations, durations, and designs. We flag these comparisons as indicative, not head-to-head.

More on how we review.

Sources

  1. Lilly. "Retatrutide delivered powerful weight loss in pivotal Phase 3 obesity trial (TRIUMPH-1)." Investor Relations, May 21, 2026. Eli Lilly and Company
  2. TRIUMPH-1 trial record, ClinicalTrials.gov NCT05929066. ClinicalTrials.gov
  3. Jastreboff AM, et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial." NEJM, 2023. New England Journal of Medicine
  4. Jastreboff AM, et al. "Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)." NEJM, 2022. New England Journal of Medicine
  5. Wilding JPH, et al. "Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1)." NEJM, 2021. New England Journal of Medicine
  6. Lilly. "Retatrutide delivered weight loss average… (TRIUMPH-4, knee osteoarthritis)." Investor Relations, December 2025. Eli Lilly and Company
  7. Lilly. "Retatrutide demonstrated significant reductions in A1C and weight in first Phase 3 diabetes trial (TRANSCEND-T2D-1)." March 19, 2026. Eli Lilly and Company (via PR Newswire)
  8. TRIUMPH Phase 3 weight-management program design; over 5,800 participants across four core trials. TRIUMPH program design publication (PubMed)
How we keep this honest
What this is
Educational information, not medical advice. It reports published research — it doesn’t recommend that you use, obtain, or supply anything.
Regulatory status
Retatrutide and similar peptides are investigational — not approved by the FDA or any regulator. Semaglutide and tirzepatide are prescription-only medicines, available only through a licensed prescriber.
Our standard
Every claim traces to a primary source. We label the strength of evidence and flag estimates as estimates — never as clinical fact.
No commercial ties
We don’t sell, supply, or link to suppliers of any medicine, and aren’t affiliated with any manufacturer.

Do not make decisions about your health without consulting a qualified healthcare provider. For trial enrolment, see ClinicalTrials.gov. More on how we review.

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