What Is Retatrutide? The Next-Gen Weight Loss Drug Explained (2026)
⚠️ Important: Retatrutide Is Not Yet Available
Retatrutide is still in clinical trials and is not FDA-approved. It cannot be legally prescribed or purchased outside of research studies. Any website selling "retatrutide" or "research peptides" is selling an unregulated, potentially dangerous product. FDA approval is expected in late 2026 or 2027.
If you’ve been following weight loss drug news, you’ve probably heard buzz about retatrutide — sometimes called the “triple G” drug. The December 2025 trial results made headlines: 28.7% average body weight loss. That’s significantly more than Zepbound or Wegovy.
So what is it, when can you get it, and is it worth waiting for? Here’s everything we know.
What Is Retatrutide?
Retatrutide (developmental code LY3437943) is an investigational weight loss medication made by Eli Lilly — the same company behind Mounjaro and Zepbound.
What makes it different: it’s a triple-agonist, meaning it mimics three hormones instead of one or two.
How Current GLP-1 Drugs Work #
| Drug | Hormones Targeted | Average Weight Loss |
|---|---|---|
| Ozempic / Wegovy (semaglutide) | GLP-1 only | ~15% |
| Mounjaro / Zepbound (tirzepatide) | GLP-1 + GIP | ~20-25% |
| Retatrutide | GLP-1 + GIP + Glucagon | ~28.7% |
The Three Hormones #
GLP-1 (glucagon-like peptide-1): Slows digestion, reduces appetite, helps regulate blood sugar. This is what Ozempic and Wegovy target.
GIP (glucose-dependent insulinotropic polypeptide): Works with GLP-1 to enhance insulin response and reduce appetite. Tirzepatide (Mounjaro/Zepbound) adds this.
Glucagon: This is the new one. Glucagon promotes fat burning, even at rest. It increases energy expenditure and helps break down stored fat. This is why retatrutide produces more weight loss — it’s not just reducing appetite, it’s actively increasing how many calories your body burns.
💡 Why "Triple G"?
Retatrutide is sometimes called "triple G" because it targets three receptors: GLP-1, GIP, and Glucagon. It's the first drug to combine all three.
Trial Results: What the Data Shows
TRIUMPH-4 (December 2025) #
The most recent major trial results came out on December 11, 2025. The headlines were impressive:
Other key findings:
- Pain reduction of 75.8% in patients with knee osteoarthritis
- Significant improvements in physical function
- More than 1 in 8 patients on retatrutide were completely free of knee pain by end of trial
- Reduced cardiovascular risk markers (cholesterol, triglycerides, blood pressure)
- Blood pressure reduction of 14 mmHg at highest dose
Phase 2 Results (Earlier Data) #
The Phase 2 trial published in the New England Journal of Medicine showed:
- 24 weeks: Up to 17.5% weight loss
- 48 weeks: Up to 24.2% weight loss
- Dose-dependent results (higher doses = more weight loss)
Retatrutide vs Zepbound vs Wegovy
How does retatrutide compare to the drugs already on the market?
| Wegovy | Zepbound | Retatrutide | |
|---|---|---|---|
| Active ingredient | Semaglutide | Tirzepatide | Retatrutide |
| Mechanism | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + Glucagon |
| Avg weight loss | ~15% | ~20-25% | ~28.7% |
| Dosing | Weekly injection | Weekly injection | Weekly injection |
| Manufacturer | Novo Nordisk | Eli Lilly | Eli Lilly |
| FDA approved | Yes | Yes | No (in trials) |
| Available now | Yes | Yes | No |
The Honest Take #
Retatrutide’s weight loss numbers are genuinely impressive — about 10-15% more body weight lost compared to Zepbound, which was already considered best-in-class.
But there are caveats:
It’s not available yet. FDA approval is likely late 2026 or 2027. That’s at least a year away.
Trials aren’t head-to-head comparisons. Retatrutide hasn’t been directly compared to Zepbound in the same study with the same conditions. The numbers look better, but we’re comparing across different trials.
New side effects. The TRIUMPH-4 trial showed a new side effect called dysesthesia (skin sensitivity/tingling) in about 20% of patients on the highest dose. This wasn’t seen with other GLP-1s.
Cost is unknown. If Zepbound is $1,000+/month, retatrutide will likely be similar or higher.
When Will Retatrutide Be Available?
Current Status (January 2026) #
Can You Get Retatrutide Now? #
No. And I want to be very clear about this.
Retatrutide is only available through clinical trials. It cannot be legally prescribed, purchased, or compounded outside of FDA-approved research studies.
🚨 Warning: Avoid "Research Peptides"
You may see websites selling "retatrutide" or "research peptides" claiming to be the same thing. These are:
- Illegal — Selling unapproved drugs is a federal crime
- Unregulated — No quality control, unknown purity
- Potentially dangerous — May contain wrong ingredients, wrong doses, or contaminants
- Not the real thing — These are not Eli Lilly products
The FDA has specifically warned against these products. Don't risk your health on unregulated substances.
What About Compounded Retatrutide? #
Unlike semaglutide and tirzepatide, retatrutide cannot legally be compounded right now.
Here’s why: Compounding pharmacies can only produce copies of FDA-approved drugs (with some exceptions during shortages). Since retatrutide isn’t FDA-approved yet, there’s no legal pathway for compounding.
This may change after FDA approval, but that’s at least a year away — and there’s no guarantee compounding will be allowed even then.
Side Effects
Retatrutide’s side effects are similar to other GLP-1 drugs, with one notable addition.
Common Side Effects #
New Side Effect: Dysesthesia #
The TRIUMPH-4 trial revealed a side effect not commonly seen with other GLP-1 drugs:
Dysesthesia (Skin Sensitivity)
About 20.9% of patients on the 12mg dose reported skin sensitivity, tingling, or tenderness to the touch. This was generally mild and rarely led to stopping treatment, but it's a new side effect that distinguishes retatrutide from other weight loss drugs.
This is likely related to the glucagon component, which isn’t present in other GLP-1 medications.
Discontinuation Rates #
In TRIUMPH-4:
- 12.2% discontinued due to adverse events on 9mg dose
- 18.2% discontinued due to adverse events on 12mg dose
- 4.0% discontinued on placebo
Some discontinuations were actually due to “excessive weight loss” — meaning the drug worked too well for some patients.
What to Do While You Wait
If retatrutide sounds appealing but you don’t want to wait 1-2 years, here are your current options:
Option 1: Tirzepatide (Zepbound) #
This is the closest thing to retatrutide currently available. It’s a dual-agonist (GLP-1 + GIP) with ~20-25% average weight loss — still very effective.
Available through:
- Insurance (if covered)
- LillyDirect ($299-449/month for brand-name)
- Telehealth platforms (compounded tirzepatide, $149-399/month)
Option 2: Semaglutide (Wegovy) #
The original GLP-1 for weight loss. ~15% average weight loss. More affordable than tirzepatide through compounding.
Available through:
- Insurance (if covered)
- Telehealth platforms (compounded semaglutide, $99-349/month)
My Recommendation #
Don’t wait for retatrutide if you’re ready to start now. Tirzepatide and semaglutide are proven, available, and effective. You can always switch to retatrutide later if it becomes available and offers something these drugs don’t.
I went the telehealth route after my insurance denied coverage. If you’re considering that path, I put together a comparison of the platforms I researched.
Frequently Asked Questions
Q: What is retatrutide?
Retatrutide is an investigational weight loss drug made by Eli Lilly. It’s a “triple-agonist” that mimics three hormones (GLP-1, GIP, and glucagon), making it potentially more effective than current options like Wegovy or Zepbound.
Q: Is retatrutide FDA approved?
No. As of January 2026, retatrutide is still in Phase 3 clinical trials. FDA approval is expected in late 2026 or early 2027 if trials remain successful.
Q: When will retatrutide be available?
If everything goes well with trials and FDA review, retatrutide could be available by prescription in 2027. There’s no guaranteed date — it depends on trial results and FDA approval.
Q: How much weight can you lose on retatrutide?
In the TRIUMPH-4 trial, patients on the 12mg dose lost an average of 28.7% of their body weight over 68 weeks. That’s approximately 71 lbs for someone starting at 250 lbs.
Q: Is retatrutide better than Zepbound?
Based on trial data, retatrutide produces more weight loss (~28.7%) than tirzepatide/Zepbound (~20-25%). However, they haven’t been directly compared in the same trial, and retatrutide has a new side effect (skin sensitivity) not seen with Zepbound.
Q: Can I get retatrutide now?
Only through clinical trials. It cannot be legally prescribed, purchased, or compounded outside of research studies. Websites selling “retatrutide” or “research peptides” are selling illegal, unregulated products.
Q: Is there compounded retatrutide?
No. Unlike semaglutide and tirzepatide, retatrutide cannot be legally compounded because it’s not FDA-approved. This may change after approval, but there’s no legal compounded retatrutide available now.
Q: Why is retatrutide called “triple G”?
It targets three hormone receptors: GLP-1, GIP, and Glucagon — all starting with “G.” This triple mechanism is why it produces more weight loss than drugs targeting just one or two receptors.
Q: What are retatrutide side effects?
Common side effects include nausea, diarrhea, vomiting, and constipation — similar to other GLP-1 drugs. A new side effect called dysesthesia (skin sensitivity/tingling) was reported in about 20% of patients on the highest dose.
Q: How is retatrutide taken?
In trials, retatrutide is given as a once-weekly injection, similar to Ozempic, Wegovy, and Zepbound.
Q: How much will retatrutide cost?
Pricing hasn’t been announced since it’s not yet approved. Based on similar drugs (Zepbound is $1,000+/month without insurance), expect retatrutide to be in a similar range, possibly higher given its novelty.
Q: Should I wait for retatrutide or start something else now?
If you’re ready to start a weight loss medication, don’t wait. Tirzepatide and semaglutide are available now and produce significant results. You can always consider retatrutide later when it becomes available.
The Bottom Line #
Retatrutide is promising, but it's not available yet.
The trial results are genuinely impressive — 28.7% average weight loss is more than any currently available medication. The triple-agonist mechanism (adding glucagon) appears to be a real advancement.
But the reality is:
- FDA approval is at least a year away (late 2026 or 2027)
- It cannot be legally obtained outside of clinical trials
- "Research peptide" versions are illegal and dangerous
- Cost will likely be $1,000+/month when it launches
- Compounded versions won't exist until after FDA approval (if at all)
My take: If you're interested in GLP-1 medications, don't wait for retatrutide. Start with what's available now — tirzepatide and semaglutide are effective and accessible today. When retatrutide becomes available, you'll have the option to switch.
I’ll keep this page updated as the FDA approval process progresses and new information becomes available.
Related Reading #
Questions? contact@glp1afterdenial.com
Last updated: January 21, 2026. I'll update this page as new trial results and FDA decisions are announced.
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