Comparisons

Wegovy vs Mounjaro: Which Is Better for You?

GLP-1 Companion · 8 min read

Wegovy (semaglutide 2.4 mg, Novo Nordisk) and Mounjaro (tirzepatide, Eli Lilly) represent two of the most effective medications available for weight management. Both are once-weekly injectables. Both produce dramatic weight loss that far exceeds what was previously possible with pharmacotherapy alone. But they are different drugs with different mechanisms and different primary FDA indications — and the landmark SURMOUNT-5 head-to-head trial has now provided direct comparative data that was previously unavailable.

What Are Wegovy and Mounjaro?

Wegovy is the brand name for semaglutide 2.4 mg, a GLP-1 receptor agonist manufactured by Novo Nordisk. It received FDA approval in June 2021 for chronic weight management in adults with a BMI of 30 or higher, or 27 or higher with a weight-related comorbidity. Mounjaro is the brand name for tirzepatide manufactured by Eli Lilly. It was originally approved in May 2022 for type 2 diabetes. Tirzepatide activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor, making it a dual incretin agonist. Zepbound is the same tirzepatide molecule approved specifically for obesity in November 2023. When patients and clinicians refer to "Mounjaro for weight loss," they are typically referring to tirzepatide used either off-label (Mounjaro) or on-label (Zepbound).

FDA Indications: A Key Distinction

• Wegovy: FDA-approved for chronic weight management (obesity or overweight with comorbidity) — NOT for type 2 diabetes
• Mounjaro: FDA-approved for type 2 diabetes — NOT for obesity
• Zepbound: FDA-approved for chronic weight management — the on-label obesity version of tirzepatide
• Important: Mounjaro and Zepbound are the same drug at the same doses in different pens with different approvals

SURMOUNT-5: The First Direct Head-to-Head Trial

Before SURMOUNT-5, comparisons between Wegovy and Mounjaro/Zepbound were based on indirect analysis of separate clinical trials with different populations, study durations, and endpoints. SURMOUNT-5, published in early 2025, was the first randomized controlled trial to directly compare tirzepatide 15 mg versus semaglutide 2.4 mg in patients with obesity (BMI ≥30 or BMI ≥27 with comorbidities) without type 2 diabetes.

• Weight loss at 72 weeks: Tirzepatide -20.2% vs semaglutide -13.7% (statistically significant difference)
• Absolute weight loss difference: Tirzepatide produced approximately 47.4 lbs vs approximately 32 lbs on semaglutide at baseline weight of ~230 lbs
• Achievement of ≥25% weight loss: 32% on tirzepatide vs 16% on semaglutide
• Discontinuation due to adverse events: 2.7% on tirzepatide vs 5.6% on semaglutide
• Serious adverse events: 8.5% on tirzepatide vs 9.4% on semaglutide

SURMOUNT-5 confirmed what separate trial data had suggested: tirzepatide produces meaningfully greater weight loss than semaglutide, with a difference of approximately 6 to 7 percentage points in body weight reduction. The tolerability finding — fewer discontinuations on tirzepatide despite greater efficacy — was particularly noteworthy.

Weight Loss Results Compared

• Wegovy (STEP 1, 68 weeks, no diabetes): Average -14.9% body weight
• Tirzepatide/Zepbound (SURMOUNT-1, 72 weeks): Average -15.0% at 5 mg, -19.5% at 10 mg, -20.9% at 15 mg
• SURMOUNT-5 direct comparison: Tirzepatide -20.2% vs semaglutide 2.4 mg -13.7%

At the population level, tirzepatide clearly outperforms semaglutide for weight loss. However, there is substantial individual variability in both directions. Some patients respond exceptionally well to semaglutide and achieve 20%+ weight loss; others may not tolerate tirzepatide escalation as well. The clinical question is never just which drug is "better on average" but which is the right fit for a specific patient.

Side Effects and Tolerability

Both medications share a GLP-1-driven side effect profile dominated by gastrointestinal symptoms, particularly during dose escalation.

• Nausea: ~44% with Wegovy vs ~12-24% with tirzepatide (dose-dependent)
• Diarrhea: ~30% with Wegovy vs ~12-17% with tirzepatide
• Vomiting: ~24% with Wegovy vs ~5-9% with tirzepatide
• Constipation: ~24% with Wegovy vs ~11-17% with tirzepatide
• Both carry black-box warnings for thyroid C-cell tumor risk
• Both are contraindicated in patients with personal or family history of medullary thyroid carcinoma or MEN2
• Pancreatitis and gallbladder disease risks are present with both agents

The SURMOUNT-5 data showing lower discontinuation on tirzepatide than semaglutide is somewhat counterintuitive given the nominally higher GI rates in some individual trial datasets, but direct comparisons in the same population paint a more favorable tolerability picture for tirzepatide.

Cost and Insurance Coverage

• Wegovy list price: approximately $1,350 per month
• Mounjaro / Zepbound list price: approximately $1,060 per month (Zepbound); Mounjaro pricing is similar
• Wegovy manufacturer savings card: $0 to $25/month for eligible commercially insured patients
• Zepbound / Mounjaro manufacturer savings card: approximately $25/month for eligible commercially insured patients
• Insurance coverage for obesity treatment: varies widely; many plans now cover both, but prior authorization is common
• Medicare coverage: historically restricted for obesity-only drugs; expanded coverage pathways are being implemented in 2026
• No generics available for either product as of April 2026

Who Should Consider Wegovy?

• Patients with obesity seeking strong weight loss (14-17% average) with well-established long-term safety data
• Patients with obesity plus cardiovascular disease: SELECT trial showed 20% CV event reduction with semaglutide 2.4 mg
• Patients who responded well to semaglutide in a lower-dose form (Ozempic) and want to escalate
• Patients whose formulary or prior authorization pathways favor Wegovy

Who Should Consider Mounjaro or Zepbound?

• Patients with obesity seeking maximum weight reduction (20%+ average at highest doses)
• Patients who did not achieve adequate weight loss on semaglutide
• Patients with type 2 diabetes and obesity (Mounjaro is approved for both; very high-efficacy option)
• Patients with insulin resistance: tirzepatide's GIP component produces complementary metabolic effects
• Patients whose formulary or savings card makes Zepbound more accessible than Wegovy

Cardiovascular Outcomes: An Important Distinction

The SELECT trial (2023) demonstrated that semaglutide 2.4 mg (Wegovy) reduces major adverse cardiovascular events by 20% in patients with obesity and established cardiovascular disease but without diabetes. This is a landmark finding that gives Wegovy an additional clinical rationale beyond weight loss for high-risk cardiovascular patients. A comparable cardiovascular outcomes trial for tirzepatide in obesity (without diabetes) has not yet been completed as of April 2026, so for patients with known cardiovascular disease, Wegovy currently has stronger evidence supporting its use.

Tirzepatide wins on average weight loss. Semaglutide has more cardiovascular outcomes data. The right answer for most patients depends on their individual risk profile, insurance, and treatment goals — not just which number is larger in a trial abstract.

The Bottom Line

The SURMOUNT-5 trial confirmed that tirzepatide (Mounjaro/Zepbound) produces greater weight loss than semaglutide (Wegovy) head-to-head — approximately 20.2% versus 13.7%. For patients whose primary goal is maximum weight reduction and who have insurance access to both, tirzepatide is the stronger agent. For patients with cardiovascular disease alongside obesity, semaglutide's SELECT trial data provides a compelling additional rationale. Both medications are transformative for obesity treatment, and the choice between them should be made with your healthcare provider based on your specific medical situation.

Sources

• Wilding et al. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. NEJM.
• Jastreboff et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. NEJM.