Retatrutide vs semaglutide: Ozempic, Wegovy and the first head-to-head result

Retatrutide vs semaglutide is the comparison most people make first, because semaglutide is the drug behind Ozempic and Wegovy. Semaglutide is approved by the FDA and acts on one hormone receptor, GLP-1 [Wegovy label, Jun 2026]. Retatrutide, from Eli Lilly, acts on three and is not approved by the FDA or any other regulator [Lilly, Oct 28, 2026]. Unlike most comparisons online, this one has a direct test behind it. Lilly ran one trial against Ozempic, in type 2 diabetes, but so far the results exist only as a press release.

Below: how the two drugs differ, what that head-to-head trial found and what it can't tell you, then weight and side effects from separate trials. After that come heart evidence, the Wegovy pill and higher dose, a three-way table with tirzepatide, and how you can get each drug. For the basics, see what is retatrutide.

What is the difference between retatrutide and semaglutide?

Semaglutide is built to copy one gut hormone. Its label calls it a GLP-1 analogue with 94% sequence homology to human GLP-1 that activates the GLP-1 receptor [Wegovy label, Jun 2026]. Retatrutide is a single molecule that activates the GLP-1, GIP and glucagon receptors [NEJM, Sep 29, 2026]. So retatrutide covers semaglutide's target and adds two more. The retatrutide mechanism of action guide explains what each receptor does.

Sources: [Lilly, Sep 29, 2026] [Drugs@FDA, NDA 209637] [Drugs@FDA, NDA 215256] [Drugs@FDA, NDA 218316] [Wegovy label, Jun 2026] [Lancet, 2022].

The two brands cover different uses. Wegovy is approved for weight loss and long-term weight maintenance in adults and in children 12 and older. It is also approved to lower heart-attack and stroke risk in adults with heart disease and obesity or overweight. A third use, under accelerated approval, is a form of fatty liver disease (MASH) with moderate to advanced scarring [Wegovy label, Jun 2026]. Ozempic's approved uses are all in type 2 diabetes: blood sugar control, plus lowering heart and kidney risks in certain patients [Ozempic label, Jun 2026]. Ozempic is not labeled for weight loss.

Retatrutide vs Ozempic: what did the head-to-head trial find?

The trial is TRANSCEND-T2D-2 (NCT06260722). Lilly enrolled 1,298 adults with type 2 diabetes whose blood sugar wasn't controlled on metformin, with or without an SGLT2 inhibitor. They were randomly assigned to retatrutide 9 mg, retatrutide 12 mg or Ozempic 2 mg, once a week for 80 weeks [Lilly, Oct 28, 2026]. Lilly chose Ozempic 2 mg because it is the highest approved dose [Lilly, Oct 28, 2026], and the Ozempic label confirms 2 mg weekly as the maximum [Ozempic label, Jun 2026].

Lilly reported these averages at 80 weeks [Lilly, Oct 28, 2026]:

A1C is the standard measure of average blood sugar over about three months. By Lilly's numbers, retatrutide lowered it more and roughly doubled the weight loss. Before you lean on that, know its limits:

• Press release only. No paper has been published. Lilly says detailed results will be presented at a future medical meeting and published in a peer-reviewed journal [Lilly, Oct 28, 2026]. The registry record had posted no results on Nov 12, 2026 [ClinicalTrials.gov, NCT06260722].
• Lilly's "efficacy estimand." The table above uses Lilly's efficacy estimand. It estimates what would have happened if everyone had stayed on their assigned drug. A figure counting everyone, including people who stopped, has not been released. In other retatrutide trials that figure has come out lower: 25.0% rather than 28.3% for 12 mg in TRIUMPH-1, for example [NEJM, Sep 29, 2026] [Lilly, May 21, 2026].
• Open label. Volunteers and doctors knew which drug each person got; the registry lists no masking [ClinicalTrials.gov, NCT06260722]. That can sway how side effects are reported and how people stick with treatment.
• Type 2 diabetes only. This tells you nothing direct about people with obesity who don't have diabetes. No head-to-head trial in that group is registered.
• Sponsor. Lilly, which makes retatrutide, ran the trial against a rival company's drug.

Side effects in the same trial were closer than many expect [Lilly, Oct 28, 2026]:

Nausea was about the same on all three arms. Skin sensitivity and stopping were more common on retatrutide, especially at 12 mg.

Retatrutide vs Wegovy for weight loss

There is no head-to-head trial in people without diabetes, so the comparison here comes from separate studies. Each one counts everyone who was randomized, whether or not they kept taking the drug.

Retatrutide's number is the largest, but these trials differ in length, timing and volunteers. STEP 1 ran 68 weeks and TRIUMPH-1 ran 80. STEP 1 volunteers started at about 105 kg [Wegovy label, Jun 2026], and TRIUMPH-1 volunteers at 112.7 kg [Lilly, May 21, 2026]. No head-to-head result in obesity exists, so the gap is a pointer, not a verdict. Every retatrutide trial result is in retatrutide weight loss results.

What about the higher Wegovy dose and the Wegovy pill?

Both now exist. The FDA approved Wegovy HD, a 7.2 mg weekly dose, on Mar 19, 2026 [Drugs@FDA, NDA 215256]. The label limits it to people who have tolerated 2.4 mg for at least 4 weeks when additional weight reduction is clinically indicated [Wegovy label, Jun 2026]. In the label's 72-week trial, people lost 18.8% on 7.2 mg, compared with 15.5% on 2.4 mg and 3.9% on placebo [Wegovy label, Jun 2026].

Wegovy tablets were approved on Dec 22, 2025 [Drugs@FDA, NDA 218316]. They carry the same weight and heart-risk uses in adults as the injection [Wegovy label, Jun 2026].

Retatrutide has no pill. Lilly says that in clinical trials it is taken as a once-weekly subcutaneous injection [Lilly, Oct 2026], and every trial we found uses that route. Lilly's own weight-loss pill, Foundayo (orforglipron), is a different molecule [Lilly, May 21, 2026].

Heart protection: what semaglutide has shown and retatrutide hasn't

This is semaglutide's clearest lead. The SELECT trial followed 17,604 adults with heart disease and overweight or obesity, but no diabetes, for an average of 39.8 months. Heart attack, stroke or heart-related death occurred in 6.5% of people on semaglutide 2.4 mg, compared with 8.0% on placebo. The hazard ratio was 0.80, meaning about 20% lower risk [NEJM, Nov 2023]. That result is why Wegovy is approved to lower heart risk [Wegovy label, Jun 2026]. Ozempic has its own heart and kidney approvals in type 2 diabetes [Ozempic label, Jun 2026].

Retatrutide has no comparable result. TRIUMPH-3 enrolled people with obesity and heart disease, but its main goal was weight loss. Heart events were rarer than expected in both groups [Lilly, Jul 23, 2026]. Lilly counted 27 heart attacks, strokes or heart deaths on retatrutide and 23 on placebo. Its 95% confidence interval for the hazard ratio, 0.64 to 1.96, means no difference in either direction can be claimed [Lilly, Jul 23, 2026]. That is Lilly's press release figure, not peer reviewed. The trial built to answer the question, TRIUMPH-Outcomes, plans about 10,000 people. The registry estimates its main results in February 2029 [ClinicalTrials.gov, NCT06383390].

Side effects compared, trial by trial

Outside the head-to-head trial, you can set each drug's main obesity data beside its own placebo. The retatrutide figures are from Lilly's TRIUMPH-1 release [Lilly, May 21, 2026]. The semaglutide figures are from the Wegovy label's pool of three trials of the 2.4 mg dose [Wegovy label, Jun 2026].

The gut side effects look much alike. Even so, the Wegovy label warns that rates from different drugs' trials cannot be directly compared [Wegovy label, Jun 2026].

Skin sensitivity is not only a retatrutide issue. On the label, it rose with the semaglutide dose: 22% on Wegovy 7.2 mg, compared with 6% on 2.4 mg and 0.3% on placebo [Wegovy label, Jun 2026]. Both drugs raise resting heart rate too. Wegovy raised it by 1 to 4 beats per minute on average compared with placebo [Wegovy label, Jun 2026]. On retatrutide, the phase 2 paper reported a dose-related rise that peaked at 24 weeks and then eased [NEJM, 2023]. See retatrutide side effects for the full list.

Retatrutide vs tirzepatide vs semaglutide

Here are the three drugs in one view. The weight figures come from each drug's main obesity trial, counting everyone randomized. They are separate trials of different lengths, so read the row as context, not a ranking.

Sources: [Drugs@FDA, NDA 215256] [Drugs@FDA, NDA 217806] [NEJM, 2021] [NEJM, 2022] [NEJM, Sep 29, 2026] [Drugs@FDA, NDA 218316] [NEJM, Nov 2023] [Mounjaro label, Aug 2026] [ClinicalTrials.gov, NCT06383390].

The two Lilly drugs get their own side-by-side page: retatrutide vs tirzepatide.

Price and access

Semaglutide is a prescription medicine you can fill today. On Nov 12, 2026, Novo Nordisk's self-pay page listed Wegovy injection at $349 a month for doses up to 2.4 mg, and $399 a month for Wegovy HD. New patients get an offer of $199 a month for the two starting doses, for two fills, through Dec 31, 2026. Wegovy tablets ran $149 to $299 a month, depending on the dose [Novo Nordisk, Nov 12, 2026]. Insurance coverage depends on your plan.

Retatrutide can't be bought legally. Lilly says it is not on the market, and it has not announced a price [Lilly, Oct 2026]. The only legal routes are a clinical trial or Lilly's expanded access program, which is limited to adults with severe obesity and serious complications, through their doctor [ClinicalTrials.gov, NCT07629401]. The retatrutide cost guide covers money and coverage, and the retatrutide for sale guide explains why online listings are illegal.

When could that change? Lilly plans to file with the FDA in Q1 2027 [Lilly, Sep 29, 2026]. Lilly calls the planned application a biologics application, but the FDA has ruled retatrutide is a drug rather than a biologic. Lilly's appeal of that ruling was undecided when we checked [7th Cir. filing, Oct 8, 2026]. The retatrutide FDA approval guide tracks each step.