What Is Retatrutide? The Next Generation of Weight Loss Medication
Retatrutide is the world's first triple-action weight loss medication — targeting three hormone receptors instead of one or two. While semaglutide (Ozempic/Wegovy) targets one receptor and tirzepatide (Mounjaro/Zepbound) targets two, retatrutide activates all three: GLP-1, GIP, and glucagon. The result? Up to 29% body weight loss in clinical trials — more than any medication before it.
Updated April 2026 · Based on published clinical trial data (NEJM, TRIUMPH program) · Developed by Eli Lilly
Quick facts about retatrutide:
✅ Triple-action: activates GLP-1, GIP, AND glucagon receptors (first of its kind)
✅ Up to 29% body weight loss in Phase 3 trials — more than Ozempic or Mounjaro
✅ Average 71.2 pounds lost in the first Phase 3 trial (TRIUMPH-4)
✅ Developed by Eli Lilly — same company behind Mounjaro and Zepbound
⏳ Not yet FDA approved — expected late 2026 to early 2027
💉 Weekly injection — same convenience as semaglutide and tirzepatide
29%
max body weight loss in Phase 3
71 lbs
average weight loss (TRIUMPH-4)
3
hormone receptors targeted
How Does Retatrutide Work?
Retatrutide is a triple hormone receptor agonist — it mimics three natural hormones at once to attack weight from multiple angles. Think of it like this: semaglutide fights weight with one weapon, tirzepatide fights with two, and retatrutide fights with three.
1
GLP-1: Kills Your Appetite
Slows stomach emptying, reduces hunger, and quiets the constant "food noise" in your brain. This is the same receptor that Ozempic and Wegovy target.
2
GIP: Boosts Fat Processing
Improves how your body processes and stores fat, enhances insulin sensitivity, and amplifies the effects of GLP-1. This is the second receptor that Mounjaro also targets.
3
Glucagon: Burns More Fat
This is what makes retatrutide unique. Glucagon receptor activation increases your body's energy expenditure, promotes fat breakdown, and reduces liver fat. No other approved weight loss drug does this.
Why the third receptor matters: GLP-1 makes you eat less. GIP helps your body process fat better. But glucagon does something neither of them can — it tells your body to actively burn stored fat for energy. That's why retatrutide's weight loss results are so much higher than anything before it.
Retatrutide vs Semaglutide vs Tirzepatide
Here's how retatrutide stacks up against the two GLP-1 medications already on the market:
← Swipe to see full table →
Clinical Trial Results: The Numbers That Changed Everything
Phase 2 Trial (48 weeks, published in NEJM)
› 338 participants with obesity
› At the highest dose (12mg): 24.2% average body weight loss
› 100% of participants on the highest dose lost at least 5% body weight
› 93% lost at least 10% of body weight
› 75% lost at least 15% of body weight
› Results were dose-dependent — higher doses = more weight loss
Phase 3: TRIUMPH-4 (68 weeks, first Phase 3 results)
› Adults with obesity AND knee osteoarthritis
› At 12mg dose: 28.7% average body weight loss
› Average weight loss: 71.2 pounds
› Substantial relief from osteoarthritis pain as added benefit
› Seven additional Phase 3 readouts expected in 2026
Side Effects: What to Expect
Retatrutide's side effects are similar to other GLP-1 medications. Most are gastrointestinal, mild to moderate, and improve over time as your body adjusts:
Common (mild, usually temporary):
› Nausea (most common, improves over time)
› Diarrhea
› Constipation
› Vomiting
› Decreased appetite (desired effect)
The good news:
› Side effects decrease with continued use
› Gradual dose titration minimizes symptoms
› No new safety signals vs existing GLP-1s
› Most patients continue treatment despite initial side effects
› Benefits significantly outweigh temporary discomfort
When Will Retatrutide Be Available?
✓
2023 — Phase 2 Results Published (NEJM)
24.2% body weight loss at highest dose. Results stunned the medical community.
✓
Dec 2025 — First Phase 3 Results (TRIUMPH-4)
28.7% weight loss + osteoarthritis pain relief. Even better than Phase 2.
→
2026 — Seven More Phase 3 Readouts Expected
Additional TRIUMPH trials for obesity, type 2 diabetes, and related conditions.
→
Late 2026 — Potential FDA Submission
If Phase 3 results remain positive, Eli Lilly could submit for FDA approval.
★
Late 2026 – Early 2027 — Estimated FDA Approval
If approved, retatrutide would likely become available through telehealth providers shortly after.
Can't Wait? Start With What's Available Now
Retatrutide is exciting — but it's not available yet. The good news? Semaglutide and tirzepatide are available TODAY through online telehealth providers, and they produce significant weight loss (15-22%) at a fraction of what retatrutide will likely cost at launch.
Many patients start with semaglutide or tirzepatide now and plan to switch to retatrutide once it becomes available. There's no reason to wait — every month counts.
Frequently Asked Questions
What is retatrutide?
Retatrutide is an investigational triple-action weight loss medication developed by Eli Lilly. It activates three hormone receptors — GLP-1, GIP, and glucagon — making it the first triple agonist for obesity treatment. In clinical trials, participants lost up to 24-29% of their body weight, significantly more than semaglutide (15%) or tirzepatide (22.5%).
Is retatrutide FDA approved?
No. As of April 2026, retatrutide is not yet FDA approved. It is currently in Phase 3 clinical trials (TRIUMPH program). Based on typical FDA timelines, approval is estimated for late 2026 to early 2027 if trials remain successful.
How much weight can you lose on retatrutide?
In the first Phase 3 trial (TRIUMPH-4), participants on the highest dose lost an average of 28.7% of their body weight — about 71.2 pounds — over 68 weeks. These results significantly exceed both semaglutide and tirzepatide.
How is retatrutide different from Ozempic and Mounjaro?
Ozempic (semaglutide) targets one receptor (GLP-1). Mounjaro (tirzepatide) targets two (GLP-1 + GIP). Retatrutide targets all three (GLP-1 + GIP + glucagon). The addition of glucagon increases fat burning and metabolism, producing greater weight loss. See our semaglutide vs tirzepatide comparison →
Can I get retatrutide now?
Retatrutide is not yet available as an FDA-approved medication. Until it receives approval, semaglutide and tirzepatide are the most effective and accessible options — available today through online telehealth providers starting at $179/month. Compare all providers →
What will retatrutide cost?
Pricing has not been announced yet. Based on Eli Lilly's pricing for Mounjaro ($1,079/month) and Zepbound ($1,086/month), brand-name retatrutide will likely cost $1,000-1,500/month without insurance. Compounded versions may become available at lower prices once the medication is on the market.
When will retatrutide be available?
Eli Lilly has seven Phase 3 trial readouts expected in 2026. If results remain positive, FDA approval could come in late 2026 or early 2027. Once approved, it will likely be available through the same telehealth providers that currently offer semaglutide and tirzepatide.
Medical Disclaimer: Retatrutide is an investigational medication not yet approved by the FDA. Information on this page is based on published clinical trial data and is for educational purposes only. Do not use any unapproved medication without consulting a licensed healthcare provider. Compounded medications are not FDA-approved as finished products. Always consult a physician before starting any weight loss medication.
