Clinical Results That Are Rewriting the Limits of Weight Loss
Retatrutide delivered up to 28.7% mean body weight reduction — an average of 71.2 lbs — in the landmark TRIUMPH-4 Phase 3 trial. Every participant on the highest dose lost at least 5% of body weight.
The Numbers Speak for Themselves
The TRIUMPH Clinical Program
TRIUMPH — Triple Receptor Agonist Intervention Utilizing Metabolic Pathways in Health — is one of the most comprehensive Phase 3 obesity programs ever conducted, spanning 8 global trials across obesity, diabetes, cardiovascular disease, liver disease, and sleep apnea.
TRIUMPH-1
Weight management in adults with obesity, without Type 2 Diabetes. Includes a nested obstructive sleep apnea substudy. Phase 3 readout expected 2026.
TRIUMPH-2
Weight management in adults with obesity who also have a T2D diagnosis, with a nested OSA substudy. Evaluates both weight and glycemic outcomes.
TRIUMPH-3
Targets adults with obesity and established cardiovascular disease — the highest-risk metabolic subgroup. A critical trial for potential CV mortality benefits.
TRIUMPH-4 ✓
First Phase 3 readout (December 2025). Obesity + knee osteoarthritis. Delivered 28.7% weight loss and 75.8% reduction in WOMAC knee pain scores.
TRIUMPH-4: The Landmark Moment
Announced December 2025 — TRIUMPH-4 delivered the highest mean weight loss ever recorded in a randomized controlled Phase 3 obesity trial in this class of therapy.
At the 12mg dose over 68 weeks. Participants lost an average of 71.2 pounds. Placebo arm lost just 2.1%.
WOMAC knee pain score reduced by an average of 4.5 points (75.8% improvement) at 12mg. More than 1-in-8 patients became completely pain free.
Every single participant in the 12mg arm achieved the clinically meaningful threshold of 5% weight loss — a result unprecedented in Phase 3 trials.
Trial Design
TRIUMPH-4 Phase 3 Weight Loss Results, 68 Weeks
Continuous, Progressive Weight Reduction
Unlike earlier GLP-1 therapies that plateau at ~6 months, retatrutide's weight loss trajectory continues to progress through 72+ weeks — suggesting a sustained biological reset, not a plateau effect.
Approximate trajectory based on Phase 2 interim data and TRIUMPH-4 final endpoints.
Cardiovascular Risk Reduction
Beyond weight loss, retatrutide produced broad improvements in cardiometabolic risk factors in TRIUMPH-4 — reducing multiple established markers of cardiovascular disease simultaneously.
How Retatrutide Compares
A direct comparison of mean weight loss across the leading GLP-1 class therapies — all from major Phase 3 randomized controlled trials.
Dramatic Pain Relief in Knee Osteoarthritis
TRIUMPH-4 was uniquely designed to evaluate retatrutide in patients with both obesity and knee osteoarthritis — two of the most co-prevalent conditions in medicine. The pain results were extraordinary.
WOMAC Pain Score Reduction
75.8%The WOMAC (Western Ontario and McMaster Universities Arthritis Index) pain score fell by an average of 4.5 points — a 75.8% improvement — in participants on 12mg.
Complete Pain Freedom
>1 in 8More than 1 out of every 8 participants on retatrutide reported being completely free from knee pain by the end of the 68-week trial — an outcome previously achievable only through surgical intervention.
Physical Function Improvement
SignificantMeasures of physical function — including stair-climbing, walking distance, and self-reported mobility — were all significantly improved, confirming that pain relief translated into real-world functional gains.
A Revolution for Fatty Liver Disease
MASLD (metabolic-associated steatotic liver disease) affects an estimated 1 in 4 adults globally. In Phase 2 trials, retatrutide delivered liver fat reductions that shocked researchers.
Highest dose — remarkable result
Transforming Blood Sugar Control
The TRANSCEND Phase 3 program evaluates retatrutide specifically in Type 2 Diabetes. Phase 2 data previewed results that rival or exceed existing best-in-class diabetes treatments.
HbA1c Reduction in T2D
In participants with Type 2 Diabetes, 36 weeks of retatrutide reduced HbA1c by 1.6% — a clinically significant improvement that would meet the bar for diabetes drug approval as a standalone outcome.
HbA1c in Non-Diabetics
Even participants without a T2D diagnosis showed HbA1c reductions of 0.4% — indicating broad metabolic normalization that may prevent the progression from pre-diabetes to Type 2 Diabetes.
Weight Loss in T2D Patients
Participants with Type 2 Diabetes — a population that historically achieves less weight loss on GLP-1 drugs — still lost a mean of 16.9% body weight at 36 weeks. This is a landmark result for a diabetic cohort.
What You Need to Know About Safety
Retatrutide's safety profile is consistent with its class. Most adverse events are gastrointestinal, dose-dependent, and transient. A new signal — dysesthesia — emerged at higher doses in TRIUMPH-4 and is under active investigation.
Common Side Effects (Class-Typical)
GI side effects are consistent with GLP-1 class. Careful dose titration significantly reduces incidence.
TRIUMPH-4 Discontinuation & New Signal
An abnormal skin sensation (dysesthesia) was reported in 20.9% of 12mg participants vs 0.7% on placebo. Eli Lilly is actively investigating this signal. Mechanism and long-term significance are under study.
Seven More Phase 3 Readouts Expected in 2026
TRIUMPH-4 was just the beginning. The full TRIUMPH, TRANSCEND, and SYNERGY programs span every major dimension of metabolic disease — with results due throughout 2026 and beyond.
TRIUMPH-1
Obesity without T2D — the core obesity indication. Primary endpoint: ≥5% weight loss responder rate and mean % body weight change vs. placebo.
TRIUMPH-2
Obesity with Type 2 Diabetes — evaluating dual benefit on weight and HbA1c. Expected to confirm and extend Phase 2 T2D data showing 16.9% weight loss.
TRIUMPH-3
Cardiovascular disease population — the highest-stakes trial for potential MACE benefit. Could position retatrutide as a successor to SELECT (semaglutide CV trial).
Type 2 Diabetes Focus
Dedicated T2D trials evaluating glycemic control as a primary endpoint — targeting regulatory approval for diabetes as a separate indication from obesity.
Liver Disease (MASLD/MASH)
Confirming Phase 2 liver fat results in full Phase 3. The 82.4% liver fat reduction seen at 12mg in Phase 2 positions retatrutide as a potential best-in-class for fatty liver disease.
Long-Term Durability
Multiple Phase 3 trials evaluate optimal maintenance dosing strategies — critical for establishing whether weight loss is sustained after the induction phase or requires ongoing therapy.
The Data Is In.
Be Among the First.
Thousands are already on the priority access list for retatrutide. Our medical team is tracking every Phase 3 readout in real time. Secure your place today.
Join the Priority Access List →Sources: Eli Lilly investor releases, TRIUMPH-4 Phase 3 topline data (Dec 2025), NEJM Phase 2 publication, PubMed systematic reviews. Retatrutide is investigational and not yet FDA-approved for commercial use.