Mounjaro vs Retatrutide: What to Know
Retatrutide is a new medication in development from Eli Lilly — the same company that makes Mounjaro. It uses three hormones instead of two.
Helpful Products for GLP-1 Treatment
Managing your GLP-1 medication is easier with the right tools:
- Sharps container — Essential for safe needle disposal. A sharps container is required for home use.
- Ginger products — Manage nausea with ginger chews or ginger tea.
- Water bottle — Stay hydrated to reduce side effects. A large water bottle helps you track intake.
- Electrolyte packets — Prevent dehydration. Liquid I.V. packets dissolve easily in water.
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Quick Comparison
| Mounjaro | Retatrutide | |
|---|---|---|
| Active drug | Tirzepatide | Retatrutide |
| Drug class | Dual GIP/GLP-1 agonist | Triple GIP/GLP-1/Glucagon agonist |
| FDA approval | Type 2 diabetes (approved) | Phase 3 trials (positive results as of May 2026) |
| Dosing | Once weekly | Once weekly (in trials) |
| Status | Available now | Phase 3 complete (not yet FDA-approved) |
What Is Retatrutide?
Retatrutide mimics three hormones:
- GLP-1 — signals fullness, slows digestion
- GIP — works with GLP-1 to boost the effect
- Glucagon — increases energy expenditure (burns more calories)
Mounjaro uses the first two. Retatrutide adds the third.
Weight Loss Results
From clinical trials (as of May 2026):
- Mounjaro: ~15-22% body weight loss at max dose
- Retatrutide (Phase 3): up to 28.7% body weight loss at 12 mg dose (TRIUMPH-4, 68 weeks)
- Retatrutide (Phase 3): up to 16.8% body weight loss in type 2 diabetes (TRANSCEND-T2D-1, 40 weeks)
Retatrutide has shown the strongest weight loss results of any GLP-1-type drug in Phase 3 trials so far — up to 28.7%. The added glucagon component appears to boost calorie burning on top of the appetite and fullness signals.
Side Effects
Based on Phase 3 trial data, Retatrutide causes similar side effects:
- Nausea
- Decreased appetite
- Increased heart rate (from the glucagon component)
- Diarrhea or constipation
- Dysesthesia (tingling or burning sensation) — more common at higher doses
The glucagon component may cause a slightly higher heart rate, which is being monitored in trials.
Availability
Retatrutide is not yet FDA-approved. Two Phase 3 trials have reported positive results. Seven more Phase 3 readouts are expected in 2026. The earliest likely FDA filing is late 2026 or 2027, with potential approval in 2027.
Cost
No pricing yet. It will likely be priced similarly to Mounjaro/Zepbound (~$1,060/month).
Who Might Benefit?
- People who plateau on tirzepatide
- People who want the strongest possible weight loss
- People who respond well to Eli Lilly medications
FAQ
When will retatrutide be available?
Retatrutide is not yet FDA-approved. Two Phase 3 trials (TRIUMPH-4 and TRANSCEND-T2D-1) have reported positive results as of May 2026, with seven more Phase 3 readouts expected in 2026. The earliest likely FDA filing is late 2026 or 2027, with potential approval in 2027.
Is retatrutide stronger than Mounjaro?
Early data suggests retatrutide may produce greater weight loss than Mounjaro. Phase 3 trials show up to 28.7% weight loss for retatrutide vs approximately 15-22% for Mounjaro at maximum dose. However, retatrutide is not yet approved and individual results may vary.
What is the main difference between Mounjaro and retatrutide?
Mounjaro (tirzepatide) targets two hormones — GLP-1 and GIP. Retatrutide targets three hormones — GLP-1, GIP, and glucagon. The added glucagon component may increase calorie burning, which could explain the stronger weight loss results seen in trials.
Should I switch from Mounjaro to retatrutide when it becomes available?
Talk to your doctor. If Mounjaro is working well for you, there may be no reason to switch. Retatrutide may be an option for people who do not get enough weight loss on current medications, but it will not be available until at least 2027.
Bottom Line
Retatrutide offers even stronger weight loss than Mounjaro in Phase 3 trials — up to 28.7% vs around 15-22%. It is not yet FDA-approved, but with positive Phase 3 results now in hand, the earliest possible approval is 2027. If Mounjaro is working for you now, there's no reason to wait. If you're not getting the results you want, talk to your doctor about current options.
Work with your healthcare provider to determine which medication is right for you. Individual results and experiences vary.