Mounjaro lowered blood sugar and weight more than Ozempic in the one trial that compared them directly. In SURPASS-2 (40 weeks, 1,879 adults with type 2 diabetes), tirzepatide cut HbA1c by up to 2.30 points versus 1.86 for semaglutide 1 mg, and up to 5.5 kg more weight. Without insurance, Mounjaro costs $499 a month; Ozempic costs $199 to $499.
Mounjaro versus Ozempic is one of the few GLP-1 matchups settled by a direct randomized trial — which makes it unusually answerable. The short version: in a head-to-head in people with type-2 diabetes, Mounjaro came out ahead on both of the numbers that matter. The longer version is worth understanding, including the important caveat that these are the diabetes brands, not the weight-loss ones.
Same families, different molecules
Both are once-weekly injections, but they are different drugs. Ozempic is semaglutide, a GLP-1 receptor agonist — it mimics one gut hormone (GLP-1). Mounjaro is tirzepatide, a “twincretin” that activates two receptors: GIP and GLP-1. That dual mechanism is the leading explanation for why it tends to outperform single-agonist GLP-1 drugs. (Their weight-management counterparts are Zepbound and Wegovy: same molecules, different brand and approval.) Ozempic also now comes as a once-daily tablet (1.5, 4 and 9 mg) under the same brand name; Mounjaro is injection-only, in single-dose pens, vials or a four-dose KwikPen.[2][3]
The head-to-head: SURPASS-2
In SURPASS-2, a 40-week trial of 1,879 adults with type-2 diabetes, tirzepatide (5, 10 or 15 mg) was compared directly against semaglutide 1 mg.[1] On blood sugar, every tirzepatide dose beat semaglutide: HbA1c fell by 2.01, 2.24 and 2.30 percentage points on tirzepatide 5, 10 and 15 mg, versus 1.86 points on semaglutide.[1]
- Semaglutide 1 mg (Ozempic)1.86 % points
- Tirzepatide 5 mg2.01 % points
- Tirzepatide 10 mg2.24 % points
- Tirzepatide 15 mg2.3 % points
Weight: Mounjaro’s edge was larger
The gap was even clearer on weight. Tirzepatide produced significantly greater weight loss than semaglutide at every dose — the difference between them growing to 5.5 kg in tirzepatide’s favor at the 15 mg dose (all comparisons p<0.001).[1] In a diabetes trial weight is a secondary outcome, but a 5.5 kg separation between two active drugs is a substantial, clinically meaningful margin.
Two limits on that result. The trial was open-label, and it used Ozempic’s 1 mg dose; the 2 mg dose approved since was not tested against tirzepatide. Side effects were similar in kind: nausea hit 17 to 22% on tirzepatide and 18% on semaglutide, and serious adverse events were reported in 5 to 7% versus 3%.[1]
| Mounjaro (tirzepatide) | Ozempic (semaglutide) | |
|---|---|---|
| Molecule | Tirzepatide | Semaglutide |
| Receptors | GIP + GLP-1 (dual) | GLP-1 (single) |
| HbA1c drop (SURPASS-2) | Up to −2.30 points | −1.86 points |
| Weight vs the other drug | Greater (up to −5.5 kg more) | Reference |
| Dosing | Once weekly injection, 2.5 to 15 mg | Once weekly injection, 0.25 to 2 mg; or a daily tablet, 1.5 to 9 mg |
| Approved for | Type 2 diabetes (adults and children 10+); lowering heart-attack, stroke and CV-death risk in type 2 diabetes at high CV risk | Type 2 diabetes (adults); lowering heart-attack, stroke and CV-death risk with established CV disease; slowing kidney decline with chronic kidney disease |
| Self-pay price | $499 a month, any dose | $349 (0.25 to 1 mg) or $499 (2 mg); $199 intro for 2 months; tablets $149 to $299 |
What does each cost without insurance?
As of October 2026, Lilly sells Mounjaro pens directly for $499 a month at every dose; its list price is $1,112.16 per fill.[5] Novo Nordisk charges new self-pay patients $199 a month for the first two fills of Ozempic 0.25 or 0.5 mg (offer through December 31, 2026), then $349 a month for 0.25 to 1 mg and $499 for 2 mg; the Ozempic tablets run $149 (1.5 mg), $199 (4 mg) and $299 (9 mg). With commercial insurance that covers the drug, either maker’s savings card can bring the copay to as little as $25.[6][5]
The honest verdict
On the evidence, Mounjaro beat Ozempic in the one trial that tested them directly — more HbA1c reduction and meaningfully more weight loss, consistent with tirzepatide’s dual-receptor mechanism.[1] That doesn’t make Ozempic a weak drug; semaglutide is highly effective and remains a first-line choice, and individual tolerability, cost, insurance coverage and side effects often decide the real-world pick. But if the question is simply “which lowered blood sugar and weight more in a head-to-head,” the answer is Mounjaro. Compare the full incretin field in our GLP-1 comparison tool, and see the routes to a prescription in our guide to GLP-1 providers.