Retatrutide vs Ozempic: The Head-to-Head Trial, A1C, Weight Loss and Doses
Retatrutide vs Ozempic: in the first head-to-head trial, A1C fell 2.2 vs 1.8 points and weight 20.9% vs 9.4%. Doses, side effects, price and status compared.
Retatrutide isn't Ozempic, and in the first trial of retatrutide vs Ozempic it lowered blood sugar more and took off more than twice the weight. In TRANSCEND-T2D-2, which Lilly reported on October 28, 2026, adults with type 2 diabetes on retatrutide 9 mg or 12 mg cut their A1C by 2.2 points over 80 weeks, against 1.8 on Ozempic 2 mg, and lost 19.5% and 20.9% of their body weight, against 9.4%. Those are Lilly's topline figures, counted as if everyone stayed on their drug. Ozempic is semaglutide, a Novo Nordisk medicine approved for type 2 diabetes that acts on one hormone receptor (GLP-1); retatrutide is an Eli Lilly molecule that acts on three and is still in Phase 3 trials.
Key takeaways
- TRANSCEND-T2D-2, reported by Lilly on October 28, 2026, is the first trial to put retatrutide head to head with Ozempic: 1,298 adults with type 2 diabetes on metformin, over 80 weeks.
- Retatrutide 12 mg lowered A1C more than Ozempic 2 mg, 2.2 points against 1.8, under the trial's strict error control. The 9 mg win on A1C is nominal only.
- Weight is the bigger gap: people on 12 mg lost 20.9% of their body weight, more than double the 9.4% on Ozempic.
- Nausea ran about the same on both drugs, but about 3 times as many people stopped 12 mg because of side effects.
- Ozempic is approved and has finished heart and kidney outcome trials. Retatrutide has neither, and its outcomes trial is estimated to finish its main phase in 2029.
This page treats Ozempic as the type 2 diabetes medicine most people know. If you're after semaglutide as a weight drug, retatrutide vs semaglutide covers Wegovy's doses and compares the two molecules across every trial. For tirzepatide's diabetes brand, see retatrutide vs Mounjaro.
Retatrutide vs Ozempic side by side
The Ozempic column comes from its June 2026 FDA label and NovoCare's prices as we checked them on October 31, 2026; the retatrutide column from Lilly's releases and the 2026 Lancet papers. Only the TRANSCEND-T2D-2 rows put both drugs in one trial.
| Retatrutide | Ozempic | |
|---|---|---|
| Ingredient and maker | Retatrutide (LY3437943), Eli Lilly | Semaglutide, Novo Nordisk |
| Receptors | GIP, GLP-1 and glucagon | GLP-1 |
| Status, as of October 2026 | Investigational, still in Phase 3; no approved version exists yet | Approved for blood sugar control, and to cut heart and kidney risk, in adults with type 2 diabetes |
| Form | Weekly injection in trials | Weekly pen, or a daily tablet (1.5, 4 or 9 mg) on a 2026 Ozempic tablet label |
| Starting dose and top dose | 2 mg, raised every 4 weeks to 4, 9 or 12 mg | 0.25 mg for 4 weeks, then 0.5 mg; up to 1 mg or 2 mg if needed |
| Half-life | About 6 days (Lilly Medical Information) | About 1 week |
| A1C change, TRANSCEND-T2D-2, 80 weeks | -2.2 points on 9 mg and on 12 mg | -1.8 points on 2 mg |
| Weight change, TRANSCEND-T2D-2 | -19.5% (9 mg), -20.9% (12 mg) | -9.4% (2 mg) |
| Heart and kidney outcome trials | None finished; TRIUMPH-Outcomes is estimated to finish its main phase in 2029 | SUSTAIN 6 (heart) and FLOW (kidney), both positive |
| US self-pay price, Oct 31, 2026 | None; there's no approved product | Pen $199 a month for the first 2 fills for new patients, then $349 (0.25 to 1 mg) or $499 (2 mg), NovoCare Pharmacy |
What happened when retatrutide met Ozempic head to head
TRANSCEND-T2D-2 randomized 1,298 adults whose type 2 diabetes wasn't controlled on metformin, with or without an SGLT2 inhibitor, to retatrutide 9 mg, retatrutide 12 mg or Ozempic 2 mg, its highest approved dose, for 80 weeks. Retatrutide started at 2 mg and stepped up every 4 weeks. People started at an average A1C of 8.3% and 102.4 kg (225.8 lb), and the trial was open label, so everyone knew which drug they were on.
The main question was modest: is 12 mg at least as good as Ozempic on A1C? It did better. The 12 mg wins over Ozempic on A1C and weight were tested under the trial's control for false positives (family-wise type 1 error). The 9 mg win on A1C is nominal only, meaning it sat outside that controlled set.
Retatrutide vs Ozempic in TRANSCEND-T2D-2
1,298 adults with type 2 diabetes on metformin, 80 weeks, open-label, efficacy estimand
That's 21.5 kg (47.4 lb) on 12 mg against 9.5 kg (20.9 lb) on Ozempic. Every figure uses the efficacy estimand, as if everyone had stayed on their drug for all 80 weeks. The everyone-randomized (treatment-regimen) results, which have run lower in other retatrutide trials, haven't been released, and there's no journal paper yet. Lilly says detailed results will come at a future medical meeting and in a journal, without dates, while about 650 people stay on retatrutide for 24 more weeks.
Our read: on blood sugar, retatrutide 12 mg beat Ozempic 2 mg by 0.4 points of A1C (our arithmetic), a real gap but a small one. On weight the gap is more than twofold, and that's where most of retatrutide's case against Ozempic sits.
Is reta the same as Ozempic?
No, although they're related. The Ozempic label describes semaglutide as a version of the gut hormone GLP-1 that shares 94% of its sequence with the human hormone. When blood sugar is high, it raises insulin release and lowers glucagon release, and it slows stomach emptying a little after meals.
Retatrutide switches on the GLP-1 receptor too, plus the receptors for GIP and glucagon. In lab cell tests reported in Nature Medicine in 2024, it was about 0.4 times as active as natural GLP-1 and 8.9 times more potent than natural GIP. Glucagon is the odd target for a diabetes drug, since it's the hormone that makes the liver release stored sugar into the blood, as MedlinePlus puts it. Yet A1C fell in every retatrutide diabetes trial so far, including the one against Ozempic.
Which hormone receptors each drug acts on
Retatrutide adds glucagon to the two receptors tirzepatide already targets
| Drug | GIP | GLP-1 | Glucagon |
|---|---|---|---|
| SemaglutideOzempic, Wegovy | No | Yes | No |
| TirzepatideMounjaro, Zepbound | Yes | Yes | No |
| RetatrutideInvestigational | Yes | Yes | Yes |
The "GLP-3" nickname for retatrutide isn't a real drug class; our page on whether retatrutide is a GLP-1 explains where it came from.
Why the separate placebo trials looked closer
Until October 2026, each drug's own placebo trial was all there was, and that made them look nearly even on blood sugar. The fairest pairing is SUSTAIN 1 (NCT02054897), the Ozempic trial in Table 3 of its label, and TRANSCEND-T2D-1. Both enrolled adults with type 2 diabetes managed by diet and exercise alone, and both counted people who stopped the drug (intent-to-treat in the label, the treatment-regimen estimand in The Lancet).
| Trial, dose and length | Starting A1C | A1C change | Beyond placebo | Weight change |
|---|---|---|---|---|
| SUSTAIN 1, Ozempic 1 mg, 30 weeks | 8.1% | -1.6 points | -1.4 | -4.7 kg |
| TRANSCEND-T2D-1, retatrutide 9 mg, 40 weeks | 7.9% | -1.86 points | -1.04 | -13.5 kg |
| TRANSCEND-T2D-1, retatrutide 12 mg, 40 weeks | 7.9% | -1.94 points | -1.12 | -15.1 kg |
Subtract each placebo group and Ozempic 1 mg comes out ahead, 1.4 points against 1.12. The placebo groups explain most of that: TRANSCEND-T2D-1's dropped 0.81 points on its own, SUSTAIN 1's dropped 0.1. Retatrutide's trial also began from a lower A1C (7.9% against 8.1%), leaving less room to fall. A head-to-head trial removes those problems, which is why TRANSCEND-T2D-2 now carries the A1C answer.
Weight is where they split
Every trial agrees on weight. SUSTAIN 1's Ozempic 1 mg group started at 96.9 kg, the same average as TRANSCEND-T2D-1, and lost 4.7 kg in 30 weeks (about 4.9%, by our arithmetic), against 15.1 kg (15.3%) in 40 weeks on retatrutide 12 mg. With both drugs in one 80-week trial, it was 20.9% against 9.4%.
Dose is likely part of the gap. Ozempic tops out at 2 mg, and in the label's 40-week trial in 961 people, 2 mg averaged 6.4 kg against 5.6 kg on 1 mg, a gap the trial couldn't separate from chance. Semaglutide's weight brand, Wegovy, goes to 2.4 mg and 7.2 mg a week, and no reported trial has tested retatrutide against those doses. In TRIUMPH-2, people with obesity and type 2 diabetes lost 18.8% on retatrutide 12 mg over 80 weeks, counting everyone randomized (The Lancet).
How much of the loss is fat rather than muscle hasn't been reported for TRANSCEND-T2D-2; our retatrutide muscle loss page covers what scans in other trials showed, and retatrutide weight loss results walks through every trial.
Ozempic doses and retatrutide doses
The Ozempic label starts everyone at 0.25 mg once a week for 4 weeks, then moves to 0.5 mg; the slow start is there to cut stomach side effects. If blood sugar needs more help, the dose can rise to 1 mg after at least 4 weeks, and to 2 mg after at least 4 weeks on 1 mg; in the 2 mg trial, A1C fell 2.1 points on 2 mg and 1.9 on 1 mg. For kidney protection, the label's target is 1 mg. A missed dose can be taken within 5 days; after that, you skip it and carry on with the usual day.
In retatrutide's Phase 3 trials, everyone started at 2 mg and stepped up every 4 weeks: straight to 4 mg, or through 4 and 6 mg to 9 mg, or through 4, 6 and 9 mg to 12 mg. Milligrams don't translate between the two molecules. Even Ozempic tablets and Rybelsus, both semaglutide, aren't swappable milligram for milligram, per their shared label. Both last about a week in the body (retatrutide half-life), hence weekly shots.
No published trial has moved people from Ozempic straight onto retatrutide. Our guide to switching from semaglutide to retatrutide covers what's known, and the retatrutide dosage page lists every trial schedule.
Is retatrutide safer than Ozempic?
Nobody can answer that yet, but TRANSCEND-T2D-2 gives the first side-effect rates for both drugs in the same people.
| Side effect, TRANSCEND-T2D-2, 80 weeks | Retatrutide 9 mg | Retatrutide 12 mg | Ozempic 2 mg |
|---|---|---|---|
| Diarrhea | 28.3% | 32.7% | 26.4% |
| Nausea | 21.2% | 23.8% | 21.3% |
| Vomiting | 10.2% | 15.0% | 13.2% |
| Constipation | 14.2% | 13.1% | 19.8% |
| Indigestion (dyspepsia) | 10.4% | 8.5% | 11.6% |
| Burning or oversensitive skin (dysesthesia) | 4.8% | 6.5% | 2.7% |
Stomach side effects ran about level, and constipation was more common on Ozempic. The differences are dysesthesia, more than twice as common on 12 mg, and quitting: 7.9% of people on 12 mg stopped because of side effects, about 1 in 13, against 2.7% on Ozempic, about 1 in 37. People knew which drug they were on, which could have colored what they reported. Our pages on retatrutide nausea and retatrutide diarrhea cover how long these last.
The bigger evidence gap runs one way. Ozempic has SUSTAIN 6, where 3,297 people with type 2 diabetes and heart or blood vessel disease had fewer heart attacks, strokes and heart deaths combined (hazard ratio 0.74), and FLOW, where 3,533 people with type 2 diabetes and kidney disease had fewer serious kidney events or heart deaths on 1 mg (hazard ratio 0.76). Retatrutide's heart data come from TRIUMPH-3, 1,949 adults with severe obesity and heart disease: 27 major heart events (MACE-3) on retatrutide (doses pooled) against 23 on placebo, a hazard ratio of 1.12 (95% confidence interval 0.64 to 1.96). Events were rarer than expected, so the range is too wide to show benefit or harm.
Severe low blood sugar didn't show up on either drug alone: none in Ozempic's monotherapy trial, per the label, and none in TRANSCEND-T2D-1, per The Lancet. On Ozempic 1 mg with a sulfonylurea, 1.2% had a severe episode; retatrutide's matching data haven't been published. Eye disease is another gap. In a 2-year Ozempic trial in people with high heart risk, diabetic eye complications happened in 3.0% against 1.8% on placebo. No retatrutide trial has reported eye outcomes, and TRANSCEND-T2D-2 excluded people being treated for diabetic eye disease.
Get medical help now
Severe belly pain that won't go away, sometimes spreading to the back, can mean pancreatitis on either drug. Also get help for vomiting or diarrhea that stops you keeping fluids down, swelling of the face or throat or trouble breathing, or shaking, sweating and confusion if you use insulin or a sulfonylurea.If you take Ozempic now
Retatrutide isn't something you can switch to at the pharmacy. No approved version exists yet, and Lilly's October 28, 2026 release says: "Anyone purporting to sell retatrutide to consumers is breaking the law." Lilly last said, on September 29, 2026, that it plans to submit retatrutide to the FDA in the first quarter of 2027 as a Biologics License Application (BLA). On October 2, 2026, the FDA decided that retatrutide is a drug, not a biological product, so an application would need to be filed under section 505 of the Federal Food, Drug, and Cosmetic Act. Lilly's appeal on that question is pending in the Seventh Circuit, and we found no ruling as of October 31, 2026. Our FDA approval page tracks it.
Ozempic has prices you can check today. On October 31, 2026, NovoCare Pharmacy listed the pen at $199 a month for the first 2 fills of 0.25 mg or 0.5 mg for new patients (through December 31, 2026), then $349 a month for 0.25 mg to 1 mg and $499 for 2 mg; tablets start at $149. Novo's ozempic.com offer says you can pay as little as $25, with savings capped at $100 a month; government beneficiaries are excluded.
Retatrutide has no official price. Vials listed online as retatrutide for sale aren't Lilly's product (is retatrutide legal explains where buyers stand), and the risk is concrete if you're on Ozempic. In a September 14, 2026 alert, Australia's TGA tested a vial sold as retatrutide after the person who used it had uncontrollable vomiting and a torn esophagus. It held no retatrutide, just semaglutide at about 8 times the level in approved products, so on top of Ozempic it would double up on the same drug. Nobody has tested the two together either, and since both act on the GLP-1 receptor, stacking them would likely pile up the same side effects.
Our read: if Ozempic has your A1C where your doctor wants it, a 0.4-point average edge is a thin reason to wait for a drug that isn't approved. If weight is the bigger problem, raise it with your prescriber now, since retatrutide won't be an option outside a trial until after an FDA decision. Questions worth taking in:
- Is my A1C at target on my current dose, and would 2 mg help?
- Would losing more weight change how my diabetes is treated?
- Is there a retatrutide trial I might qualify for? (Retatrutide near me lists recruiting sites.)
- If I use insulin or a sulfonylurea, how would any change affect my risk of low blood sugar?
Frequently asked questions
Is reta the same as Ozempic?
No. Ozempic is semaglutide, made by Novo Nordisk, and it acts on one hormone receptor, GLP-1. Retatrutide is a different molecule from Eli Lilly that acts on GIP, GLP-1 and glucagon receptors. Ozempic is approved for type 2 diabetes, while retatrutide is still in Phase 3 trials.
Is retatrutide better than Ozempic?
In the only head-to-head trial so far, it did more on both blood sugar and weight. In TRANSCEND-T2D-2, A1C fell 2.2 points on retatrutide 12 mg against 1.8 on Ozempic 2 mg over 80 weeks, and weight fell 20.9% against 9.4%. Those are Lilly's topline figures under the efficacy estimand, with no journal paper yet, and more people stopped retatrutide because of side effects.
Is reta safer than Ozempic?
Nobody can say yet. In TRANSCEND-T2D-2, nausea was about the same (23.8% on 12 mg vs 21.3% on Ozempic 2 mg), but 7.9% stopped 12 mg because of side effects against 2.7% on Ozempic. Ozempic also has years of use and finished heart and kidney outcome trials, and retatrutide has neither. Products sold online as retatrutide carry extra risks because nobody can verify what's in them.
Is retatrutide like Ozempic?
In some ways. Both are once-weekly injections, both act on the GLP-1 receptor, and both cause nausea, diarrhea and vomiting, mostly while the dose is going up. Retatrutide also acts on the GIP and glucagon receptors, runs on a different dose scale (2 mg to 12 mg against 0.25 mg to 2 mg), and caused much more weight loss in trials.
Why is retatrutide better than Ozempic for weight loss?
The likeliest reasons are its two extra receptor targets and its dose range, though nobody has measured how much each contributes in people. In TRANSCEND-T2D-2, Ozempic ran at 2 mg, its top dose for diabetes. Semaglutide's weight brand, Wegovy, goes to 2.4 mg and 7.2 mg, and no reported trial has tested retatrutide against those doses.
Can I switch from Ozempic to retatrutide?
Not legally outside a trial. No approved version exists yet, and Lilly's October 28, 2026 release says anyone selling retatrutide to consumers is breaking the law. No published trial has moved people from Ozempic straight onto retatrutide, so there's no tested switching schedule either.
Sources
- Lilly's retatrutide delivered greater A1C reduction and more than double the weight loss of Ozempic's highest approved dose in head-to-head trial. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Ozempic (semaglutide) injection: prescribing information. U.S. National Library of Medicine, DailyMed, 2026. dailymed.nlm.nih.gov
- Get your GLP-1 medications delivered with NovoCare Pharmacy. Novo Nordisk, 2026. novocare.com
- Rybelsus and Ozempic (semaglutide) tablets: prescribing information. U.S. National Library of Medicine, DailyMed, 2026. dailymed.nlm.nih.gov
- What is the mechanism of action of retatrutide?. Eli Lilly and Company (Lilly Medical Information), 2025. medical.lilly.com
- The Effect of Retatrutide Once Weekly on Cardiovascular Outcomes and Kidney Outcomes in Adults Living With Obesity (TRIUMPH-Outcomes, NCT06383390). ClinicalTrials.gov, 2026. clinicaltrials.gov
- Effect of Retatrutide Compared With Semaglutide in Adult Participants With Type 2 Diabetes and Inadequate Glycemic Control With Metformin With or Without SGLT2 Inhibitor (TRANSCEND-T2D-2, NCT06260722). ClinicalTrials.gov, 2026. clinicaltrials.gov
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nature Medicine, 2024. pmc.ncbi.nlm.nih.gov
- Glucagon injection. MedlinePlus, U.S. National Library of Medicine, 2026. medlineplus.gov
- Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial. The Lancet, 2026. doi.org
- TRIUMPH-2: retatrutide in adults with obesity and type 2 diabetes (Bellido V et al., Lancet 2026;408(10563):1455-1472). The Lancet, 2026. doi.org
- Lilly's triple agonist, retatrutide, successful in two additional Phase 3 obesity trials, delivering significant improvements in weight and A1C. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Wegovy (semaglutide) injection and tablets: prescribing information. U.S. National Library of Medicine, DailyMed, 2026. dailymed.nlm.nih.gov
- Lilly's triple agonist, retatrutide, delivered substantial weight loss and A1C reduction, underscoring its potential promise for people with obesity and type 2 diabetes. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- FDA letter to Eli Lilly and Company on the regulatory status of retatrutide (Oct 2, 2026), filed in Eli Lilly and Company v. Kennedy, 7th Cir. No. 26-1301. U.S. Food and Drug Administration (via CourtListener), 2026. storage.courtlistener.com
- Eli Lilly and Company v. Robert Kennedy Jr., No. 26-1301 (7th Cir.), docket. CourtListener, 2026. courtlistener.com
- Save on Ozempic. Novo Nordisk, 2026. ozempic.com
- TGA tests counterfeit retatrutide product following serious adverse event report. Therapeutic Goods Administration (Australia), 2026. tga.gov.au
Dr. Juan Pablo Frías, MD
Physician-Scientist & Clinical Trialist • Endocrinology, Diabetes & Metabolism
Dr. Frías earned his M.D. from Vanderbilt University School of Medicine and completed his endocrinology fellowship at UC San Diego. A principal investigator on landmark incretin trials (including retatrutide, tirzepatide and semaglutide), he reviews all guides on Retatrutide360 for clinical accuracy, dosing safety and evidence fidelity.
Related guides & clinical tools
Continue reading our evidence-backed guides and use our syringe calculation tools.
Retatrutide vs Mounjaro
Retatrutide vs Mounjaro in type 2 diabetes: matched 40-week trials plus each drug's head-to-head with semaglutide, for A1C, weight, nausea, heart data and cost.
Retatrutide Weight Loss Results
Retatrutide weight loss averaged up to 28.3% in TRIUMPH-1, and 20.9% vs 9.4% on Ozempic head to head. Every trial by dose, who lost less, what averages hide.
Retatrutide Nausea and Vomiting
Retatrutide nausea hit 42.4% of people on 12 mg in TRIUMPH-1, vs 14.8% on placebo. See how long it lasts, why a 2 mg start helps, and what else eases it.
Turn any dose into syringe units
Vial, water and dose in, exact syringe units out. Calculates reconstitution volumes and needle tick marks for 5 mg to 60 mg vials with zero guesswork.