Retatrutide vs Semaglutide: How the Triple Agonist Compares
Quick answer: Retatrutide produced more weight loss than semaglutide in trials — 28.3% against 14.9% for standard-dose Wegovy. But that comparison is outdated on both sides. Higher-dose semaglutide reached 20.7%, and there is now an oral version. More importantly, semaglutide is the only one of these drugs with proven cardiovascular outcome benefit, while retatrutide’s cardiovascular results in July 2026 were not statistically significant. Retatrutide is also not approved and cannot be prescribed.
The Three-Way Picture
Most comparisons treat this as retatrutide versus semaglutide. In practice people are choosing between three drugs, and tirzepatide sits between them.
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Receptor targets | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + glucagon |
| Brand names | Wegovy, Ozempic, Rybelsus | Zepbound, Mounjaro | None |
| Maker | Novo Nordisk | Eli Lilly | Eli Lilly |
| Pivotal trial weight loss | 14.9% at 68 wks (STEP 1) | 22.5% at 72 wks | 28.3% at 80 wks |
| Higher-dose result | 20.7% at 72 wks (STEP UP, 7.2 mg) | — | 30.3% at 104 wks (BMI ≥35 extension) |
| Oral form | Yes — 25 mg tablet | No | No |
| Proven CV outcome benefit | Yes — SELECT | Not established | Not established |
| FDA approved | Yes | Yes | No |
Retatrutide and tirzepatide are the closest pairing of the three, and a direct head-to-head trial between them is already running — the detailed head-to-head with tirzepatide covers what TRIUMPH-5 is designed to settle.
Weight Loss: Why the Usual Comparison Is Out of Date
The figures repeated across most articles are 28.3% for retatrutide and 14.9% for semaglutide — a gap that looks decisive. Two things have changed.
Semaglutide has a higher dose now. The STEP UP trial tested 7.2 mg against the standard 2.4 mg and produced 20.7% weight loss at 72 weeks. The MHRA authorised that strength in January 2026, becoming the first regulator in the world to do so. Comparing retatrutide against the 2.4 mg figure measures it against a dose that is no longer the ceiling.
Estimands differ. Trials report two ways. The efficacy estimand measures people who stayed on treatment as directed; the treatment-regimen estimand includes everyone regardless. Oral semaglutide illustrates the spread neatly — OASIS 4 reported 13.6% on the treatment-regimen basis and roughly 16.6–17% among adherent participants. Comparing one drug’s adherent figure against another’s all-comers figure inflates any gap, and it happens constantly.
On like-for-like current data the honest read is roughly 28% against 21%, not 28% against 15%. Still a real advantage for retatrutide, but a narrower one than usually presented — and it comes from separate trials that were never designed to be compared. The complete Phase 3 results set out the retatrutide side by dose and endpoint.
Separate trials, different durations and populations — not head-to-head comparisons
Sources: STEP 1 (N Engl J Med 2021), STEP UP, OASIS 4, SURMOUNT-1 (Eli Lilly 2022), TRIUMPH-1 (Eli Lilly 2026). Durations range from 64 to 80 weeks and populations differ, so these are indicative rather than measured comparisons. Retatrutide is investigational and not FDA approved.
Where Semaglutide Is Ahead: Cardiovascular Outcomes
This is the part that gets lost when weight loss is the only metric, and it is the strongest argument for semaglutide.
The SELECT trial established that semaglutide reduces major adverse cardiovascular events — cardiovascular death, heart attack, stroke — in people with overweight or obesity and established cardiovascular disease. That produced an FDA indication for cardiovascular risk reduction, which no other drug in this class holds for a weight-management population. Semaglutide also carries an indication in liver disease.
Retatrutide’s position on this is now known, and it is weaker. TRIUMPH-3, reported on 23 July 2026, enrolled 1,949 adults with severe obesity and established cardiovascular disease. Weight loss was strong at 22.6%. The cardiovascular results were not:
- MACE-5 hazard ratio 0.82 (95% CI 0.55–1.22) — favourable direction, not statistically significant
- MACE-3 hazard ratio 1.12 (95% CI 0.64–1.96) — not statistically significant
Event rates were low, which widens those intervals, and TRIUMPH-Outcomes is still running. So this is an absence of proof rather than proof of absence. But it means that today, on the outcome that determines whether a weight-loss drug prevents disease rather than only reducing body mass, semaglutide has demonstrated benefit and retatrutide has not.
Weight loss is one column of several
Sources: SELECT trial 2023; Eli Lilly TRIUMPH-3 topline 23 July 2026 (MACE-5 HR 0.82, 95% CI 0.55–1.22; MACE-3 HR 1.12, 95% CI 0.64–1.96); Novo Nordisk oral Wegovy approval December 2025. TRIUMPH-Outcomes, retatrutide’s dedicated cardiovascular trial, has not reported.
For someone with existing cardiovascular disease, that reverses the ranking entirely.
The Oral Option
Semaglutide is available as a daily tablet. The FDA approved oral Wegovy 25 mg in December 2025, and it launched in the US in January 2026 at $149 per month — the cheapest entry point in the class.
OASIS 4 produced 13.6% mean weight loss at 64 weeks, rising to roughly 16.6% among adherent participants. Responder rates were substantial: 50% of participants lost at least 15% of body weight, and 29.7% lost at least 20%.
Retatrutide is injection-only, as is tirzepatide. For people who will not or cannot inject weekly, the comparison ends there — a tablet that produces 13–17% beats an injection they will not take.
Side Effects Compared
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Gastrointestinal effects | Yes, dose-dependent | Yes, dose-dependent | Yes, dose-dependent |
| Dysesthesia | Not characteristic | Not characteristic | 12.5–20.9% at 12 mg |
| Heart rate increase | Class effect | Class effect | 5–10 bpm, larger |
| Real-world safety data | Years, millions of patients | Years, millions | None — trials only |
| Cardiovascular outcomes trial | Completed (SELECT) | Completed | Ongoing |
All three share the gastrointestinal profile of the incretin class, concentrated during dose escalation. Dysesthesia — altered skin sensation — is specific to retatrutide and dose-dependent; the full adverse event data by dose covers the rates and how they differ between trials.
The bottom two rows carry more weight than the rest. Semaglutide has been used by millions of people over years, which surfaces rare events that trials of a few thousand cannot detect. Retatrutide has no post-approval data at all.
Availability and Cost
| Semaglutide (Wegovy) | Tirzepatide (Zepbound) | Retatrutide | |
|---|---|---|---|
| Prescription available | Yes | Yes | No |
| Self-pay, injectable | $199–$349 | $299–$449 | N/A |
| Self-pay, oral | From $149 | N/A | N/A |
| With insurance + savings card | ~$25 | ~$25 | N/A |
| Expected availability | Now | Now | 2028 projected |
Eli Lilly said on 23 July 2026 that it will file a Biologics License Application for retatrutide in Q1 2027, which puts a realistic FDA decision in late 2027 or the first half of 2028 — the current filing and approval status is updated as milestones land. For what it is likely to cost once approved, see the full pricing breakdown.
Which Is Right for Whom
If you have established cardiovascular disease, semaglutide is the only option with proven outcome benefit and an FDA indication for it.
If maximum weight loss is the priority, retatrutide leads on trial data — but it cannot be prescribed, so the practical choice today is tirzepatide.
If you will not inject, oral semaglutide is the only option, and at $149 a month it is also the cheapest.
If tolerability matters most, semaglutide has the longest real-world safety record and no dysesthesia signal.
If you are willing to wait, retatrutide is projected for 2028, and TRIUMPH-5 — the direct head-to-head against tirzepatide — reports in 2027.
For trial data, dosing schedules, safety findings, and regulatory tracking on all of the above, browse the complete retatrutide library.
Frequently Asked Questions
Is retatrutide better than semaglutide?
On weight loss, retatrutide produced more in trials — around 28% versus 21% for higher-dose semaglutide. On proven cardiovascular benefit, semaglutide is ahead: SELECT demonstrated MACE reduction, while retatrutide’s TRIUMPH-3 cardiovascular results were not statistically significant. And semaglutide is approved while retatrutide is not.
Retatrutide vs semaglutide vs tirzepatide — which produces the most weight loss?
Retatrutide at 28.3%, tirzepatide at 22.5%, semaglutide at 14.9% standard dose or 20.7% at 7.2 mg. These come from separate trials with different durations and populations, so they are indicative rather than measured comparisons.
Is retatrutide the same as Ozempic or Wegovy?
No. Ozempic and Wegovy are brand names for semaglutide, a single GLP-1 agonist. Retatrutide is a different molecule targeting three receptors, made by a different company, and it has no brand name because it is not approved.
Can I switch from semaglutide to retatrutide?
Not currently — retatrutide cannot be prescribed. No study has examined switching between them, so there is no evidence base even for after approval.
Which has fewer side effects?
All three share the gastrointestinal profile of the class. Retatrutide adds dose-related dysesthesia, which neither of the others produces. Semaglutide has years of real-world safety data that retatrutide entirely lacks.
Is there a pill version of retatrutide?
No. Retatrutide is injection-only in every trial. Semaglutide is the only drug in this comparison available as a tablet.
When can I get retatrutide instead of semaglutide?
Eli Lilly plans to file in Q1 2027, putting a realistic FDA decision in late 2027 or the first half of 2028 and availability in 2028.
Sources
ClinicalTrials.gov: TRIUMPH-1 (NCT05929066), TRIUMPH-5 (NCT06662383).
Wilding JPH, et al. “Once-Weekly Semaglutide in Adults with Overweight or Obesity” (STEP 1). N Engl J Med. 2021.
Wharton S, Lingvay I, Bogdanski P, et al. OASIS 4 study group. Oral semaglutide 25 mg in adults with obesity.
SELECT trial. Semaglutide effects on cardiovascular outcomes in people with overweight or obesity, 2023.
Novo Nordisk. Wegovy tablets FDA approval, 22 December 2025; US launch January 2026.
Eli Lilly. TRIUMPH-1 topline, 21 May 2026; TRIUMPH-2 and TRIUMPH-3 topline, 23 July 2026.
Eli Lilly. SURMOUNT-1, April 2022; SURMOUNT-5 head-to-head, N Engl J Med 2025.