Anyone who has worked out that Wegovy is the higher-dose version of Ozempic will reach for the same shortcut on the tirzepatide pair and get it wrong. Mounjaro and Zepbound list the same six strengths, climb in the same 2.5 mg increments, stop at the same 15 mg, and ship in the same four presentations. There is no stronger brand. The differences are entirely in what each product is approved to treat, who is allowed to take it, and how it is paid for — and the rung-by-rung reading of the ladder itself is in the dose article.
The dosing sections are nearly a copy of each other
Mounjaro starts at 2.5 mg once weekly and increases in 2.5 mg increments after at least four weeks on the current dose where more glycemic control is needed, to a maximum of 15 mg in adults and 10 mg in pediatric patients.[1] Zepbound starts at the same 2.5 mg, states that the dose is for initiation and is not approved as maintenance, then moves to 5 mg and climbs by the same increments to the same 15 mg maximum.[2]
The one substantive divergence is which rungs count as destinations. Zepbound names 5, 10 and 15 mg as the maintenance doses for weight reduction and 10 or 15 mg for sleep apnea, leaving 7.5 and 12.5 mg as steps.[2] Mounjaro sets no equivalent list, because its dose is titrated to a laboratory value rather than to a target weight. Both labels list single-dose pens and vials, four-dose multi-dose vials and a four-dose KwikPen in every one of the six strengths.[1][2]
Two indication lists that barely touch
Mounjaro is indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients aged 10 and over with type 2 diabetes, and to reduce the risk of major adverse cardiovascular events in adults with type 2 diabetes at high risk for them.[1]
Zepbound is indicated, with a reduced-calorie diet and increased physical activity, to reduce excess body weight and maintain the reduction in adults with obesity or with overweight plus a weight-related condition, and to treat moderate to severe obstructive sleep apnea in adults with obesity.[2] Both labels state that coadministration with another tirzepatide product or with any GLP-1 receptor agonist is not recommended, which rules out the arithmetic some readers attempt across the two names.
The cardiovascular claim is on the diabetes brand, and it is narrower than it sounds
This is where the semaglutide intuition inverts. With that molecule the cardiovascular indication sits on the obesity brand, from a placebo-controlled superiority trial. With tirzepatide it sits on the diabetes brand, and it comes from SURPASS-CVOT, an active-comparator-controlled noninferiority trial: 13,299 patients with type 2 diabetes and atherosclerotic cardiovascular disease randomized to tirzepatide up to 15 mg or to dulaglutide 1.5 mg, an agent already shown to reduce cardiovascular events.[3]
A primary end-point event occurred in 801 patients (12.2%) on tirzepatide and 862 (13.1%) on dulaglutide, a hazard ratio of 0.92 (95.3% CI, 0.83 to 1.01), with P = 0.003 for noninferiority and P = 0.09 for superiority.[3] Tirzepatide was not shown to beat the comparator. There was no placebo arm, so the trial establishes that tirzepatide is not worse than a drug that works, which is a different sentence from the one a marketing page will write.
The enrolled population is worth naming, because it is nothing like the person buying tirzepatide on a cash plan. Mean age was 64.1 years, mean glycated hemoglobin 8.4%, mean diabetes duration 14.7 years, and 29.0% were women.[3] Gastrointestinal adverse events were more common on tirzepatide, with overall adverse-event rates similar between arms. A result earned in that cohort transfers poorly to a 45-year-old with a body-mass index of 33 and no diagnosis, which is the population Zepbound is labeled for and in which no cardiovascular outcome trial of tirzepatide has reported.
What each brand’s own trials measured
Zepbound’s weight indication rests on SURMOUNT-1, which randomized 2,539 adults with obesity and without diabetes and reported a mean change of −20.9% at 15 mg over 72 weeks against −3.1% on placebo.[4] The trial is unpacked in the SURMOUNT-1 article, and the full dose-by-dose distribution is in the weight-loss article.
The same molecule does less when diabetes is present. SURMOUNT-2 randomized 938 adults with type 2 diabetes and a body-mass index of 27 or higher, and least-squares mean weight change at 72 weeks was −14.7% at 15 mg and −12.8% at 10 mg against −3.2% on placebo.[5] Six percentage points separate the two populations at the same dose, and the split between the two approvals is the subject of the two-approvals article.
Zepbound’s second indication has no semaglutide equivalent. Two 52-week trials in adults with moderate-to-severe obstructive sleep apnea and obesity reported a change in the apnea-hypopnea index of −25.3 events per hour against −5.3 on placebo in participants not using positive airway pressure, and −29.3 against −5.5 in those who were — treatment differences of −20.0 and −23.8 events per hour.[6] What that does and does not replace is covered in the sleep apnea article.
Mounjaro’s glycemic record includes the one randomized head-to-head against semaglutide: 1,879 patients with type 2 diabetes, 40 weeks, tirzepatide at 5, 10 or 15 mg against semaglutide 1 mg, with glycated hemoglobin falling 2.30 points at 15 mg against 1.86, and weight differences of −1.9, −3.6 and −5.5 kg.[7] That comparison is read in full in the cross-molecule article.
Price, and the quality of the evidence about price
Because the products are pharmaceutically identical, any price gap between them is a statement about coverage rather than about the drug. A diabetes prescription moves through long-established reimbursement; a weight prescription frequently does not, and the direct-purchase vial channels each manufacturer runs exist precisely because of that gap. A quoted monthly figure therefore says more about which indication a prescription was written against than about which product arrives, and a price attached to a dose rather than to a box is the only kind that can be compared between the two names at all.
The published economics should be read with the funder attached. An industry-sponsored simulation using head-to-head trial data estimated lifetime savings of $41,688 per patient and 0.506 quality-adjusted life years gained for tirzepatide over semaglutide.[8] A systematic review for the American College of Physicians that deliberately excluded industry-sponsored evaluations reached a blunter conclusion: across nine studies and 42 pairwise comparisons, none carried high certainty, and only four studies were at low risk of bias.[9] Modeled savings are not observed savings.
What neither brand has been shown to do
Two absences are worth stating because the overlapping labels make them easy to miss. No cardiovascular outcome trial of tirzepatide has reported in people with obesity and without type 2 diabetes, so the indication Zepbound is most often bought for carries no outcome claim of its own. And the sleep apnea result is an airway measurement: the endpoint was the apnea-hypopnea index, not cardiovascular events, hospital admissions or mortality.[6]
On the other side, Mounjaro’s cardiovascular indication is bounded by the trial that produced it — adults with type 2 diabetes at high risk — and says nothing about primary prevention. Neither label supports the general claim that tirzepatide reduces cardiovascular risk in anyone who takes it.
What a compounded vial inherits from neither label
Everything above describes two approved products. Compounded tirzepatide is not FDA-approved and is not reviewed by the FDA for safety, efficacy or quality before dispensing, so it carries no indication, no approved maximum, no pediatric age floor and none of the trial evidence attached to either brand — the regulatory distance is set out in the compounding article, and the prices for that route are on the tirzepatide board.
The practical reading is short. There is no dose advantage to chase between these two names, so the question is which indication fits, which one a plan will pay for, and what the same milligram costs through each channel. How figures here are established before publication is described in the methodology.