Retatrutide TRIUMPH-1 Results (May 2026): 30.3% Weight Loss, Phase 3 Primary Trial
Updated June 10, 2026 (ADA 2026 full dataset): Retatrutide Phase 3 program complete. Obesity (TRIUMPH-1): 28.3% weight loss at 80 weeks, 30.3% at 104 weeks, 65.3% achieved BMI <30. T2D (TRANSCEND-T2D-1): A1C −2.0%, weight −16.8%. Comorbidities (ADA June 2026): TRIUMPH-4 knee OA, WOMAC pain score −4.0 points (≈75% reduction) vs −2.1 placebo; 14.1% pain-free on 9mg vs 4.2% placebo. TRIUMPH-1 OSA secondary: 60.6% AHI reduction (58.6 → ~23 events/hr). NDA expected Q4 2026.
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Updated June 10, 2026, ADA 86th Scientific Sessions complete: Eli Lilly's TRIUMPH-1 Phase 3 trial, the primary obesity study for retatrutide, has reported results. Across 2,339 adults with obesity, the 12mg dose delivered 28.3% average weight loss at 80 weeks (~70.3 lbs); the 9mg dose delivered 25.9%. In a study extension for BMI ≥35 participants, the 12mg dose reached 30.3% average weight loss at 104 weeks (~85 lbs), the highest sustained weight loss ever recorded in a Phase 3 obesity trial, and the first time any drug has crossed 30% in a pivotal trial. Most striking: 65.3% of participants on the 12mg dose reduced their BMI below 30 by week 80, meaning nearly two-thirds crossed the clinical obesity threshold on a drug alone. ADA 2026 comorbidity data (June 2026): TRIUMPH-4 revealed that retatrutide 9mg reduced WOMAC knee pain scores by ~4.0 points (≈75% improvement from baseline) vs 2.1 points for placebo, and 14.1% of patients on 9mg achieved complete pain relief vs 4.2% on placebo. A secondary analysis of TRIUMPH-1 showed 60.6% reduction in apnea-hypopnea index (AHI), from 58.6 to approximately 23 events per hour, in participants with moderate-to-severe obstructive sleep apnea. Additionally, retatrutide completed its first Phase 3 type 2 diabetes trial (TRANSCEND-T2D-1, 537 patients): A1C fell 1.7–2.0% and weight fell 11.5–16.8% at 40 weeks. Retatrutide is the first triple-agonist: it simultaneously activates GLP-1, GIP, AND glucagon (GCGR) receptors. FDA approval is expected late 2027 to early 2028, retatrutide is NOT available to prescribe today.
Quick answer: what's available right now while you wait for retatrutide:
- •Highest approved weight loss: Tirzepatide (Zepbound), 20.9% via LillyDirect $299/mo or Enhance MD from $99 first month compounded
- •Lowest-cost featured GLP-1: Yucca Health $146/mo compounded semaglutide
- •Brand Wegovy: NovoCare $349/mo, 14.9% loss. Or telehealth via Hers $149/mo (cheapest brand Wegovy via the 2026 Novo partnership).
- •Pill (no injection): Foundayo from $149/mo, 12.4% loss
- •Full pipeline: Next weight loss drugs guide covers retatrutide, CagriSema, MariTide, survodutide.
This guide covers retatrutide's mechanism, Phase 3 trial results, side effect profile, expected pricing, and approval timeline, based on Eli Lilly's TRIUMPH clinical program data. Compare all currently-approved GLP-1 providers or take the match quiz to find an option available today.
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Compare all 52GLP-1 providers →What Makes Retatrutide Different: Three Receptors Instead of One
Current GLP-1 medications work by activating one or two hormone receptors. Retatrutide is a first-in-class triple agonist that simultaneously activates three:
| Receptor | What It Does | Drugs That Use It |
|---|---|---|
| GLP-1 | Reduces appetite, slows gastric emptying | Wegovy, Ozempic, Saxenda (all current GLP-1s) |
| GIP | Enhances insulin secretion, may increase thermogenesis | Zepbound, Mounjaro (dual agonists) |
| Glucagon (GCGR) | Increases metabolic rate, promotes fat burning | Retatrutide ONLY (first drug to add this) |
The glucagon receptor activation is the key differentiator. Glucagon increases your resting energy expenditure and promotes fat oxidation, essentially, your body burns more fat even at rest. This third mechanism may explain why retatrutide's weight loss numbers exceed anything seen before in clinical trials.
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How Much Weight Does Retatrutide Help You Lose?
Retatrutide has been studied in both Phase 2 and Phase 3 trials. The results are striking.
The Phase 2 trial (published in the New England Journal of Medicine, June 2023) enrolled 338 adults with obesity or overweight and tested multiple doses over 48 weeks:
| Dose | Weight Loss at 48 Weeks | Notes |
|---|---|---|
| Placebo | -2.1% | Control group |
| 1 mg | -8.7% | Lowest dose |
| 4 mg | -17.1% | Comparable to semaglutide 2.4mg |
| 8 mg | -22.8% | Comparable to tirzepatide 15mg |
| 12 mg | -24.2% | Exceeded all existing GLP-1 results |
At the 12mg dose, the responder rates were remarkable: 100% of participants achieved at least 5% weight loss, 93% achieved 10%+, 83% achieved 15%+, and 26% lost more than 30% of their body weight.
Then in December 2025, Eli Lilly reported the first Phase 3 results from TRIUMPH-4 (445 participants with obesity and knee osteoarthritis, 68 weeks):
| Arm | Weight Loss | Absolute Loss |
|---|---|---|
| Retatrutide 12mg | -28.7% | ~71 lbs (32.3 kg) average |
| Retatrutide 9mg | -26.4% | ~64 lbs (29.1 kg) average |
| Placebo | -2.1% | N/A |
Then on May 21, 2026, Eli Lilly reported results from TRIUMPH-1, the primary Phase 3 obesity trial and the dataset that will anchor the NDA submission. With 2,339 participants over 80 weeks, TRIUMPH-1 is the definitive efficacy record:
| TRIUMPH-1 (80 Weeks) | Weight Loss | Notes |
|---|---|---|
| Retatrutide 12mg | -28.3% (~70.3 lbs) | 45.3% of patients achieved ≥30% loss |
| Retatrutide 9mg | -25.9% | Comparable to high-dose tirzepatide |
| Placebo | N/A | 4.9% discontinued for AEs |
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Online weight-loss program by Yucca Health, Inc. (Beverly Hills, CA). Two named board-certified doctors, Dr. Michael Wasef MD and Dr. Andrew Sakla DO, handle prescribing. 20,000+ patients, 4.6 stars across 1,065 verified Trustpilot reviews. Starts at $146/mo for compounded semaglutide (custom-made version, not the FDA-approved brand) on the 6-month plan. Buy-now-pay-later via Klarna, Affirm, or Afterpay spreads the upfront commitment.
How It Compares to Current GLP-1s
| Drug | Receptors | Max Weight Loss | Trial Duration | Status |
|---|---|---|---|---|
| Semaglutide (Wegovy) | GLP-1 | ~15-17% | 68 weeks | FDA approved (2021) |
| Tirzepatide (Zepbound) | GLP-1 + GIP | ~22-26% | 72 weeks | FDA approved (2023) |
| Retatrutide | GLP-1 + GIP + Glucagon | ~28-30% (obesity); 16.8% (T2D) | 80-104 weeks (TRIUMPH-1); 40 weeks (TRANSCEND-T2D-1) | Phase 3 complete (obesity + T2D), NDA expected Q4 2026 |
Early body composition data suggests retatrutide may also have favorable effects on fat vs. muscle loss. In available analyses, fat mass accounted for approximately 67% of total weight lost with retatrutide, compared to about 61% with semaglutide. Tirzepatide showed the best fat-to-lean ratio at roughly 75% fat loss. These are preliminary comparisons across different trials, not head-to-head data.
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Take the 60-sec QuizSide Effects: What the Trials Show
The side effect profile is similar to existing GLP-1s, with one notable new signal:
| Side Effect | Retatrutide 12mg | Context |
|---|---|---|
| Nausea | Up to 43% | Similar to Wegovy (44%) |
| Diarrhea | ~33% | Slightly higher than Wegovy (30%) |
| Constipation | ~25% | Comparable to Wegovy (24%) |
| Vomiting | ~21% | Similar to Wegovy (25%) |
| Dysesthesia (tingling/burning skin) | 20.9% at 12mg | NEW, not seen with other GLP-1s |
Discontinuation rates in TRIUMPH-1 were 11.3% at 12mg, 6.9% at 9mg, and 4.1% at 4mg, versus 4.9% for placebo, lower than TRIUMPH-4's 18.2% at 12mg, likely reflecting the longer titration schedule in TRIUMPH-1 improving tolerability. Most GI side effects were mild to moderate and improved during dose escalation. Retatrutide did not increase serious adverse events versus placebo.
When Will Retatrutide Be FDA-Approved?
- •Current status (June 10, 2026): ADA 86th Scientific Sessions (June 5–8, 2026) complete. Full TRIUMPH-1 and TRANSCEND-T2D-1 datasets presented. Comorbidity highlights: TRIUMPH-4 knee OA, 75% WOMAC pain reduction (9mg), 14.1% pain-free vs 4.2% placebo. TRIUMPH-1 OSA secondary, 60.6% AHI reduction. TRANSCEND-T2D-1 T2D, A1C −2.0%, weight −16.8% at 40 weeks. NOT approved anywhere globally.
- •TRIUMPH-1 Phase 3 complete May 2026, primary obesity trial. TRIUMPH-4 (obesity + osteoarthritis) complete December 2025. TRIUMPH-1 OSA secondary data presented ADA June 2026.
- •NDA submission to FDA: Expected Q4 2026. TRIUMPH-1 completion enables Lilly to finalize the core efficacy data package for filing.
- •FDA review: Standard review takes 10 months. Priority Review could shorten to 6 months.
- •Potential FDA approval: Late 2027 to early 2028.
- •Commercial launch: Estimated early 2028.
No brand name has been announced yet. Pricing is expected to be in the $1,000-1,500/month range at list price, similar to or slightly above current tirzepatide pricing, given its superior efficacy data.
What This Means for You
Retatrutide is not available yet, and won't be for at least 18-24 months. If you're considering GLP-1 treatment now, the currently approved options, semaglutide (Wegovy) and tirzepatide (Zepbound), are effective and available today. There's no reason to wait for retatrutide if you qualify for treatment now.
However, if you're already on a GLP-1 and interested in what's next, TRIUMPH-1's completion (May 2026) is the key milestone, Lilly can now compile the primary efficacy dataset for NDA filing. The novel dysesthesia signal (20.9% at 12mg, 8.8% at 9mg) will require explicit patient labeling and likely a structured titration protocol to minimize it. Patients considering the 9mg dose may see a favorable risk-benefit profile: 25.9% weight loss with substantially lower dysesthesia incidence. We'll update this article as the NDA filing and FDA review milestones are announced.
In the meantime, check our provider rankings to find the best GLP-1 program available today, or use our cost calculator to estimate what you'd pay with your insurance.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting any medication. Information is current as of the publication date but may change.
Affiliate Disclosure: Some links in this article are affiliate links. We may earn a commission if you sign up through our links, at no extra cost to you.
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News & PipelineNext Weight Loss Drugs Pipeline (2026): Retatrutide 28.7%, CagriSema 22.7%, MariTide Monthly
Side Effects & SafetyZepbound Side Effects (2026): Nausea 29%, Diarrhea 23%, Vomiting 13%, Full Guide with SURMOUNT Trial Data
What the doctors say
Verbatim, independently sourced statements from named physicians and medical bodies, real clinicians quoted with their sources, not a single paid reviewer. General clinical context, not an endorsement of any provider.
“Patients on both medications experienced substantial weight loss, and we observed no difference in the risk of gastrointestinal adverse events. In addition to effectiveness, factors like medication availability and insurance coverage will likely play a role in deciding which medication to initiate.”
“For more than a million people at high risk of heart attack and stroke, this treatment on the NHS could be life-changing – offering a powerful new way to protect their hearts and improve their health.”
“So-called 'weight loss drugs' like semaglutide have proven benefits beyond reducing the number on the scales – they are now considered important medicines for preventing deadly heart attacks and strokes. Today's guidance will no doubt help save lives as cardiovascular disease is still one of the country's biggest killers.”
Quotes are general medical commentary about GLP-1 medications, independently sourced and not solicited by GLP-1 Picks. They are not an endorsement of any provider, our provider scores are set solely by our published methodology.