Wegovy vs Mounjaro
Obesity-Approved Semaglutide vs T2D-Approved Tirzepatide — Weight Loss Compared
Wegovy (semaglutide 2.4 mg) is specifically approved for obesity. Mounjaro (tirzepatide 15 mg) is approved for type 2 diabetes but frequently considered for weight loss given SURMOUNT trial data showing ~20.9% mean body weight reduction. For patients choosing between them, the key question is efficacy vs on-label status. Track either in Shotlee to monitor your personal response.
Mechanism of Action
- →GLP-1 receptor agonist — single incretin mechanism
- →FDA-approved for obesity (BMI ≥30 or ≥27 + comorbidity)
- →Suppresses appetite via hypothalamic GLP-1 receptors
- →Slows gastric emptying, prolonging satiety
- →SELECT trial: 20% MACE reduction in obesity + CVD
- →Half-life ~7 days; once-weekly autoinjector pen
- →STEP-1: 14.9% mean body weight loss at 68 weeks
- →Dual GIP + GLP-1 receptor agonist
- →FDA-approved for T2D; Zepbound brand for obesity
- →GIP agonism enhances adipose insulin sensitivity
- →GIP co-signalling may reduce GLP-1-driven nausea
- →SURMOUNT-1: 20.9% mean body weight loss at 72 weeks
- →Half-life ~5 days; once-weekly autoinjector pen
- →SURPASS-CVOT 2024: 15% MACE reduction vs placebo
Head-to-Head Comparison
| Factor | Wegovy | Mounjaro |
|---|---|---|
| Active molecule | Semaglutide | TirzepatideBest |
| Receptor targets | GLP-1 only | GIP + GLP-1 |
| FDA obesity approval | Yes (June 2021) | No — Zepbound brand for obesity |
| Max dose | 2.4 mg weekly | 15 mg weekly |
| Weight loss (STEP-1/SURMOUNT-1) | 14.9% at 68 wks | 20.9% at 72 wks |
| Nausea incidence | ~44% (STEP-1) | ~31% (SURMOUNT-1 15 mg) |
| Cardiovascular outcome trial | SELECT 2023: 20% MACE reduction | SURPASS-CVOT 2024: 15% MACE reduction |
| Off-label use for weight loss | N/A — on label | Common when Zepbound not covered |
| Monthly cost (uninsured) | ~$1,300–1,400 | ~$1,000–1,200 |
| T2D brand | Ozempic | Mounjaro |
Weight Loss: The Numbers
Choose Based on Your Goal
Maximum weight loss
Tirzepatide (Mounjaro/Zepbound) shows ~20.9% vs Wegovy's 14.9% in individual trials, and is directly superior in SURMOUNT-5 (2025).
On-label obesity treatment
Wegovy is specifically FDA-approved for obesity. If your primary diagnosis is obesity, Wegovy (or Zepbound for tirzepatide) is on-label.
Cardiovascular risk reduction
Wegovy's SELECT trial (2023) showed a 20% MACE reduction in obesity + CVD. Mounjaro's SURPASS-CVOT (2024) showed 15%. Both have positive CV data.
Lower nausea rates
Trial data suggests tirzepatide has lower nausea (~31% vs ~44% for semaglutide). GIP modulation may reduce GI side effects.
Insurance coverage
Mounjaro for T2D has better insurance coverage than Wegovy for obesity. If you have T2D, Mounjaro may be more accessible.
You want the obesity-approved obesity drug
For pure on-label obesity pharmacotherapy, compare Wegovy vs Zepbound (the obesity-approved tirzepatide brand).
Which Is Right for You?
For maximum weight loss, tirzepatide has consistently outperformed semaglutide in head-to-head data. SURMOUNT-5 (2025) directly compared them and found tirzepatide produced ~47% more relative weight loss. If maximum weight reduction is the priority and you have T2D or your plan covers Zepbound, tirzepatide is the evidence-based choice.
Wegovy has two key advantages: it is on-label for obesity (giving prescribers and patients confidence), and the SELECT trial showed a 20% MACE reduction in obesity with CVD — currently the strongest cardiovascular outcome data for an obesity drug. Mounjaro's SURPASS-CVOT (2024) showed 15% MACE reduction but in a T2D population.
For patients without T2D who are choosing between Wegovy and Mounjaro specifically, note that Mounjaro's obesity data comes from SURMOUNT trials under the Zepbound brand — the Mounjaro label is for T2D. Your prescriber can prescribe Mounjaro off-label for weight loss, but Zepbound is the indicated brand for that purpose.
Wegovy vs Mounjaro: Frequently Asked Questions
Yes, by trial data. Tirzepatide 15 mg (Mounjaro/Zepbound) achieved ~20.9% body weight loss in SURMOUNT-1 vs ~14.9% for semaglutide 2.4 mg (Wegovy) in STEP-1. The 2025 SURMOUNT-5 direct head-to-head confirmed tirzepatide's superiority.
Wegovy's SELECT trial (2023) showed a 20% MACE reduction in non-diabetic patients with obesity and CVD — the first obesity drug to demonstrate this. Mounjaro's SURPASS-CVOT (2024) showed a 15% MACE reduction in T2D patients with CVD.
Mounjaro is FDA-approved for type 2 diabetes. Zepbound — the same tirzepatide molecule at the same doses — is approved for obesity. Doctors can prescribe Mounjaro off-label for weight loss.
Mounjaro is typically slightly less expensive uninsured (~$1,000–1,200/month) vs Wegovy (~$1,300–1,400). Eli Lilly also offers lower-cost Zepbound vials for self-pay patients.
Yes, with prescriber guidance. No washout period is required. Standard practice is to start tirzepatide at 2.5 mg regardless of prior semaglutide dose and escalate normally. Track both in Shotlee to compare your response.
Track Wegovy or Mounjaro in Shotlee
Log doses, weight progress, and side effects for either drug. Free for iOS and Android.
📚References & sources
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