Ozempic arrived first, in December 2017. Mounjaro followed in May 2022 [8] [9]. They do the same job, controlling blood sugar in type 2 diabetes, with different molecules from different companies. If you're comparing them for weight loss instead, the weight-labeled versions are compared in Zepbound vs Wegovy.
Two different molecules: Mounjaro isn't a semaglutide
Ozempic contains semaglutide, which acts on the GLP-1 receptor. Mounjaro contains tirzepatide, which acts on GLP-1 and on a second gut-hormone receptor, GIP. Both help the pancreas release insulin when blood sugar rises, slow the stomach and reduce appetite. Neither is insulin. The semaglutide vs tirzepatide comparison covers the molecules in depth, and Zepbound vs Mounjaro explains how Mounjaro relates to Lilly's weight-loss brand.
Blood sugar: Mounjaro lowered A1C more in SURPASS-2
SURPASS-2 randomized 1,879 adults with type 2 diabetes who were already on metformin. Their average A1C, the three-month blood sugar measure, started at 8.28%. Over 40 weeks, it fell by 2.01, 2.24 and 2.30 points on Mounjaro 5, 10 and 15 mg, and by 1.86 points on semaglutide 1 mg. Every Mounjaro dose met the trial's bar for being better [1].
Three caveats. Eli Lilly, Mounjaro's maker, funded the trial, and it was open-label. The semaglutide dose was 1 mg, while Ozempic's label now goes up to 2 mg a week. And the gap at the lowest Mounjaro dose was small, 0.15 points [1]. Low blood sugar was rare in all groups, from 0.2% to 1.7% on Mounjaro and 0.4% on semaglutide.
Heart and kidneys: Ozempic has the longer record
| Ozempic | Mounjaro | |
|---|---|---|
| Active ingredient | Semaglutide (Novo Nordisk) | Tirzepatide (Eli Lilly) |
| First approval | December 2017 | May 2022 |
| A1C in SURPASS-2 | −1.86 points (1 mg) | −2.01 to −2.30 points |
| Weight in SURPASS-2 | Reference | 4.2 to 12.1 pounds (1.9 to 5.5 kg) more lost |
| Heart-risk indication | Type 2 diabetes with heart disease (SUSTAIN-6) | Type 2 diabetes at high heart risk, August 2026 (SURPASS-CVOT) |
| Kidney indication | Type 2 diabetes with chronic kidney disease, January 2025 (FLOW) | None |
| Children | Not approved | 10 and older, December 2025 |
| Tablet sibling | Ozempic tablets, same maker | None |
| Label dose range | Starts at 0.25 mg; up to 2 mg weekly | Starts at 2.5 mg; up to 15 mg weekly (10 mg in children) |
| Self-pay from the maker | $349 a month up to 1 mg, $499 at 2 mg, after an intro offer | $499 a month at every strength |
SURPASS-2 [1]; Ozempic label [5]; Mounjaro label [6]; prices [10] [11].
- SUSTAIN-6 (Ozempic's heart trial). In 3,297 adults with type 2 diabetes at high heart risk, semaglutide lowered heart attacks, strokes and heart deaths to 6.6% from 8.9% on placebo (hazard ratio 0.74). Diabetic eye complications were more common on semaglutide (hazard ratio 1.76) [2].
- FLOW (Ozempic's kidney trial). In 3,533 adults with type 2 diabetes and chronic kidney disease, semaglutide 1 mg cut major kidney events by 24% and was stopped early for benefit [3].
- SURPASS-CVOT (Mounjaro's heart trial). About 13,000 adults with type 2 diabetes and heart disease took tirzepatide or dulaglutide, an older GLP-1 drug. Major heart events occurred in 12.2% and 13.1%; tirzepatide met the bar for being no worse, not for being better [4]. Lilly funded it.
So both now carry heart-risk indications, from different kinds of trial. Ozempic's was tested against placebo; Mounjaro's against another active drug. Only Ozempic has a kidney indication.
Weight loss: Mounjaro lost more, but neither is a weight drug
In SURPASS-2, people lost 4.2, 7.9 and 12.1 pounds (1.9, 3.6 and 5.5 kg) more on Mounjaro 5, 10 and 15 mg than on semaglutide 1 mg [1]. That was a secondary result in people with diabetes. Neither Ozempic nor Mounjaro is FDA-approved for weight loss. Each has a weight-labeled twin with the same molecule: Wegovy for semaglutide and Zepbound for tirzepatide. If weight is the main goal, Zepbound vs Wegovy covers that trial and those labels.
Doses, forms and children
Both are once-weekly injections. Ozempic's label starts at 0.25 mg and allows up to 2 mg a week; Mounjaro's starts at 2.5 mg and allows up to 15 mg in adults [5] [6]. The milligram numbers aren't comparable across molecules, and your prescriber sets the steps in between.
Only Ozempic has a pill version. Ozempic tablets, renamed from a newer Rybelsus formulation in January 2026, are approved for blood sugar control and heart-risk reduction in type 2 diabetes [7]. The semaglutide pill guide explains the tablets. Only Mounjaro is approved for children: from age 10, with type 2 diabetes. Ozempic's label says its safety and efficacy haven't been established in children [5].
Side effects are similar, and low blood sugar depends on your other medicines
Ozempic's most common side effects are nausea, vomiting, diarrhea, abdominal pain and constipation [5]. Mounjaro's are nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion and abdominal pain [6]. In SURPASS-2 nausea affected 17% to 22% of people on Mounjaro and 18% on semaglutide; serious adverse events were 5% to 7% against 3% [1].
Both labels warn that low blood sugar is more likely when either drug is combined with insulin or a sulfonylurea, and both carry the same boxed warning about thyroid C-cell tumors in rodents. For a full rundown, see the Mounjaro safety guide and the Ozempic safety guide.
Which fits depends on what else you're managing
- Lowering A1C as far as possible. Mounjaro had the larger drop in SURPASS-2, against Ozempic's 1 mg dose.
- Chronic kidney disease alongside diabetes. Ozempic is the one labeled to slow kidney decline.
- Diabetic eye disease. Tell your prescriber either way; SUSTAIN-6 saw more eye complications on semaglutide, and both labels warn about it.
- A child or teen with type 2 diabetes. Mounjaro is approved from age 10; Ozempic isn't approved for children.
- Wanting a pill. Ozempic tablets are the only option of the two.
Cost: Ozempic is cheaper in cash below 2 mg; insurance is the usual route
For type 2 diabetes, most people get these drugs through insurance. Without it, both makers sell direct. NovoCare charges new Ozempic patients $199 for each of the first two months at 0.25 mg and 0.5 mg (through December 31, 2026), then $349 a month for doses up to 1 mg and $499 at 2 mg. The Ozempic pill starts at $149 a month for 1.5 mg [10]. LillyDirect lists Mounjaro at $499 a month at every strength [11].
So at the same $499, Mounjaro covers its whole dose range, while Ozempic costs $150 less unless you need 2 mg. The Ozempic cost guide and Medicare coverage guide go deeper; the Ozempic guide and Mounjaro guide cover each drug on its own. For people weighing metformin first, metformin vs Ozempic covers that step.