# Retatrutide vs Semaglutide vs Tirzepatide: 2026 Comparison Source: https://www.dietglp.com/blog/retatrutide-vs-semaglutide-vs-tirzepatide/ Published: 2026-11-07 Keywords: retatrutide vs semaglutide vs tirzepatide, retatrutide vs tirzepatide vs semaglutide, retatrutide vs semaglutide, retatrutide vs semaglutide for weight loss, retatrutide vs semaglutide side effects, retatrutide vs semaglutide dosage chart, is retatrutide stronger than semaglutide, retatrutide vs semaglutide which is better, retatrutide vs tirzepatide vs semaglutide muscle loss, retatrutide vs tirzepatide vs semaglutide side effects, retatrutide vs tirzepatide vs semaglutide for weight loss, switching from semaglutide to retatrutide, what is retatrutide similar to, is retatrutide a semaglutide **TL;DR:** Retatrutide, tirzepatide and semaglutide all act on the GLP-1 receptor, but tirzepatide adds GIP and retatrutide adds GIP and glucagon. In their main obesity trials, average weight loss for people who stayed on the top dose was about 17% for semaglutide 2.4 mg, 22.5% for tirzepatide 15 mg and 28.3% for retatrutide 12 mg, though the trials were run separately. Semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro) are FDA approved; retatrutide is not, and Lilly plans to file in early 2027. On any of them, [Sharpy](https://apps.apple.com/us/app/glp-diet-app-sharpy/id6762084138) helps you hit one protein target and one 20-minute workout a day so you keep more muscle. People keep asking how the three big weekly shots stack up: retatrutide vs semaglutide vs tirzepatide. **The short answer: retatrutide has shown the most weight loss in trials, tirzepatide is next, and semaglutide is third, but only semaglutide and tirzepatide are approved and sold today.** Retatrutide is still an Eli Lilly study drug. Here is how they compare on results, side effects, doses, muscle, price and status as of November 7, 2026. ## Retatrutide vs semaglutide vs tirzepatide at a glance | | Semaglutide | Tirzepatide | Retatrutide | |---|---|---|---| | Maker | Novo Nordisk | Eli Lilly | Eli Lilly | | Receptors it acts on | GLP-1 | GLP-1, GIP | GLP-1, GIP, glucagon | | Brand names | Wegovy (shot and pill), Ozempic, Rybelsus | Zepbound, Mounjaro | None yet | | How it is taken | Weekly shot or daily pill | Weekly shot | Weekly shot (in trials) | | FDA approved | Yes | Yes | No | | Nickname | "GLP-1" | "Dual agonist" | "Triple agonist" or "triple G" | Each one builds on the last. GLP-1 and GIP are gut hormones that help with appetite and blood sugar. Glucagon may raise how much energy the body burns. Adding receptors is the reason the newer drugs have shown bigger numbers. ## Retatrutide vs semaglutide vs tirzepatide for weight loss No trial has tested all three together. These are the main obesity trials for each, in adults without diabetes. The numbers estimate the result if people stayed on the top dose for the whole trial. | Main obesity trial | Drug and top dose | Length | Average weight loss | |---|---|---|---| | STEP 1 | Semaglutide 2.4 mg (Wegovy) | 68 weeks | about 16.9% | | STEP UP | Semaglutide 7.2 mg (Wegovy HD) | 72 weeks | about 20.7% | | SURMOUNT-1 | Tirzepatide 15 mg (Zepbound) | 72 weeks | 22.5% | | TRIUMPH-1 | Retatrutide 12 mg | 80 weeks | 28.3% (placebo 2.2%) | Counting everyone who started, including people who quit, the numbers are lower: 14.9% in STEP 1 and 20.9% in SURMOUNT-1. In TRIUMPH-1, 45.3% of people on retatrutide 12 mg lost at least 30% of their weight, Lilly said. These trials enrolled different people for different lengths of time, so the gaps are a rough guide, not a final score. ## What the head-to-head trials show Two of the three pairings have now been tested directly. | Head-to-head trial | Who was in it | Result | |---|---|---| | SURMOUNT-5 (tirzepatide vs semaglutide) | 751 adults with obesity, no diabetes, 72 weeks | 20.2% vs 13.7% weight loss | | TRANSCEND-T2D-2 (retatrutide vs semaglutide) | 1,298 adults with type 2 diabetes, 80 weeks | 19.5% (9 mg) and 20.9% (12 mg) vs 9.4% on Ozempic 2 mg | | TRIUMPH-5 (retatrutide vs tirzepatide) | About 800 adults with obesity | Not reported yet | TRANSCEND-T2D-2 results are Lilly's topline numbers from October 28, 2026, and are not in a journal yet. People with type 2 diabetes usually lose less weight on every one of these drugs, which is why those numbers look smaller. Our [retatrutide vs Ozempic guide](/blog/retatrutide-vs-ozempic/) has the full table, and [semaglutide vs tirzepatide](/blog/semaglutide-vs-tirzepatide/) covers SURMOUNT-5 in detail. ## Retatrutide vs tirzepatide vs semaglutide side effects All three mostly cause stomach side effects, worst while the dose is going up. The table uses the top weight-loss dose from each drug's main trial or label. | Side effect | Semaglutide 2.4 mg (Wegovy label) | Tirzepatide 15 mg (Zepbound label) | Retatrutide 12 mg (TRIUMPH-1) | |---|---|---|---| | Nausea | 44% (placebo 16%) | 28% (placebo 8%) | 42.4% (placebo 14.8%) | | Stopped due to side effects | 6.8% (placebo 3.2%) | 6.7% (placebo 3.4%) | 11.3% (placebo 4.9%) | Two points stand out. First, more people stopped retatrutide 12 mg than the top approved doses of the other two. Second, retatrutide trials keep showing dysesthesia, a change in skin feeling such as tingling, burning or sensitivity. Lilly says it was mostly mild. The approved drugs also carry label warnings for rarer problems such as [pancreatitis](/blog/glp1-and-pancreatitis/) and gallbladder disease, and retatrutide's long-term safety is still being studied. ## Retatrutide vs semaglutide dosage chart This chart shows dose ranges only. It is not a schedule to follow. Your prescriber sets your dose and how fast it goes up. | | Semaglutide (Wegovy shot) | Tirzepatide (Zepbound) | Retatrutide | |---|---|---|---| | Starting dose | 0.25 mg weekly | 2.5 mg weekly | Not set (trials started at 2 mg) | | Highest dose | 2.4 mg weekly; 7.2 mg for Wegovy HD | 15 mg weekly | Not set (trials tested 4, 9 and 12 mg) | | Official label | Yes | Yes | No | The milligrams are not comparable across drugs. Retatrutide 12 mg is not "five times" Wegovy 2.4 mg; they are different molecules. Anyone selling a retatrutide "dosing chart" with vials is selling an unapproved product. ## Which one loses the most muscle? This is the question that matters most for how you look and feel after the weight comes off, and it is the least answered. In a body-scan part of STEP 1, about 39% to 40% of the weight lost on semaglutide was lean mass. In SURMOUNT-1, about 25% of the loss on tirzepatide was lean mass. Those used different methods, so they are not a clean win for tirzepatide. We could not find published body-scan results from the retatrutide Phase 3 trials as of November 7, 2026. What is clear: the more weight you lose, the more muscle you can lose with it unless you fight back. Two habits do most of the work, eating enough protein and lifting something heavy a few times a week. [Sharpy](https://apps.apple.com/us/app/glp-diet-app-sharpy/id6762084138) turns that into one daily [protein target](/blog/protein-target-on-glp1/), one 20-minute strength workout and one Shape Score, so you can see whether the loss is mostly fat. New to lifting? Start with our [beginner strength program](/blog/beginner-strength-program-glp1/). ## Price and how to get each one | | Semaglutide (Wegovy) | Tirzepatide (Zepbound) | Retatrutide | |---|---|---|---| | Self-pay price | $349 a month for most doses; $399 for Wegovy HD | $299 to $449 a month, depending on dose | No price; not for sale | | Where | Pharmacies, NovoCare, telehealth | Pharmacies, LillyDirect, telehealth | Clinical trials only | | Insurance | Varies by plan | Varies by plan | None | Lilly has said it plans to file retatrutide with the FDA in early 2027, so a launch before late 2027 is unlikely. Lilly also says retatrutide "cannot be legally sold" to consumers today. Our [retatrutide price guide](/blog/retatrutide-price/) and [is retatrutide legal?](/blog/is-retatrutide-legal/) explain why online "research peptide" vials are a bad bet. ## So which is better? It depends on what you can actually get and what your body tolerates. - **Semaglutide** has the longest track record and a proven heart attack and stroke benefit in adults with heart disease and excess weight. - **Tirzepatide** causes more weight loss than semaglutide in a direct trial, with similar stomach side effects. - **Retatrutide** has the biggest trial numbers so far, but more people quit the top dose, it is not approved, and its head-to-head with tirzepatide has not reported. If your current drug is working, there is no reason to chase the next one. If it is not, talk to your prescriber about approved options now. For the wider field, see our [GLP-1 drugs list](/blog/glp-1-drugs-list/) and the full [retatrutide guide](/blog/retatrutide-guide/). If you are tired of weekly shots, our [MariTide guide](/blog/maritide/) covers Amgen's once-monthly drug, which is still in Phase 3. ## The bottom line Retatrutide beats semaglutide head to head and has the highest weight loss in trials, tirzepatide beats semaglutide head to head, and retatrutide vs tirzepatide is still unknown. Only semaglutide and tirzepatide can be prescribed today. Whichever you use, protect your muscle as the scale drops: [Sharpy](https://apps.apple.com/us/app/glp-diet-app-sharpy/id6762084138) keeps it to one protein target, one 20-minute workout and one Shape Score a day. ## Sources - [Lilly's triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial (TRIUMPH-1), Eli Lilly, May 21, 2026](https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-delivered-powerful-weight-loss) - [Lilly's retatrutide head-to-head trial vs Ozempic (TRANSCEND-T2D-2), Eli Lilly via PR Newswire, October 28, 2026](https://www.prnewswire.com/news-releases/lillys-retatrutide-delivered-greater-a1c-reduction-and-more-than-double-the-weight-loss-of-ozempics-highest-approved-dose-in-head-to-head-trial-302921328.html) - [TRIUMPH-5, retatrutide vs tirzepatide, ClinicalTrials.gov NCT06662383](https://clinicaltrials.gov/study/NCT06662383) - [Wilding et al. STEP 1, semaglutide 2.4 mg in adults with obesity. NEJM 2021](https://www.nejm.org/doi/full/10.1056/NEJMoa2032183) - [Jastreboff et al. SURMOUNT-1, tirzepatide for obesity. NEJM 2022](https://www.nejm.org/doi/full/10.1056/NEJMoa2206038) - [Aronne et al. SURMOUNT-5, tirzepatide vs semaglutide. NEJM 2025](https://www.nejm.org/doi/full/10.1056/NEJMoa2416394) - [Wegovy and Zepbound prescribing information, FDA (Drugs@FDA)](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm) ## Frequently asked questions **Q: Which is stronger: retatrutide, tirzepatide or semaglutide?** A: For weight loss, retatrutide has shown the biggest numbers, then tirzepatide, then semaglutide. In TRIUMPH-1, adults without diabetes lost 28.3% on retatrutide 12 mg at 80 weeks if they stayed on the drug. Tirzepatide beat semaglutide head to head in SURMOUNT-5 (20.2% vs 13.7%), and retatrutide beat semaglutide head to head in TRANSCEND-T2D-2 (up to 20.9% vs 9.4% in people with type 2 diabetes). Retatrutide vs tirzepatide has not reported yet. **Q: Is retatrutide a semaglutide?** A: No. They are different molecules from different companies. Semaglutide is made by Novo Nordisk and acts on one receptor, GLP-1. Retatrutide is made by Eli Lilly and acts on three: GLP-1, GIP and glucagon. They are in the same broad family of weekly incretin shots. **Q: Retatrutide vs semaglutide side effects: which is worse?** A: Stomach side effects look similar in kind: nausea, diarrhea, constipation and vomiting. In TRANSCEND-T2D-2, more people stopped retatrutide 12 mg for side effects (7.9%) than Ozempic 2 mg (2.7%), and dysesthesia, an odd tingling or burning skin feeling, was more common on retatrutide. Semaglutide also has years of real-world safety data that retatrutide does not have yet. **Q: Is there a retatrutide vs semaglutide dosage chart?** A: Only for the approved drugs. Wegovy shots go from 0.25 mg up to 2.4 mg a week, with Wegovy HD at 7.2 mg. Zepbound goes from 2.5 mg up to 15 mg a week. Retatrutide has no label: Phase 3 trials tested 4 mg, 9 mg and 12 mg a week. Doses of different drugs cannot be swapped milligram for milligram, and your prescriber sets your dose. **Q: Can I switch from semaglutide to retatrutide?** A: Not legally today. Retatrutide is not approved by the FDA or any other regulator, and Lilly says anyone selling it to consumers is breaking the law. The only legal way to get it now is a clinical trial. If semaglutide is not working well enough, ask your prescriber about approved options such as tirzepatide or Wegovy HD. **Q: Which causes the most muscle loss?** A: No trial has measured that across all three. In a body-scan part of STEP 1, about 39% to 40% of the weight lost on semaglutide 2.4 mg was lean mass; in SURMOUNT-1, about 25% on tirzepatide. Those trials used different methods. We could not find published body-scan results from retatrutide Phase 3 trials as of November 7, 2026. Bigger loss raises the stakes for protein and strength training on any of them.