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Wegovy vs Zepbound (2026) Updated · 17d ago

Quick answer: Wegovy (semaglutide) achieves 14-15% average body-weight loss at 68 weeks. Zepbound (tirzepatide) achieves 20-21% — Zepbound wins on efficacy. Costs similar ($1,000-1,350/mo retail). Side effects similar (mostly GI). Mounjaro and Ozempic contain the same molecules but are FDA-approved for diabetes rather than weight loss.

Clinically reviewed by Editorial Medical Review, MD, NAMS-CMP · Last updated 2026-05-22

How they work

Wegovy

Semaglutide is a GLP-1 receptor agonist. Mimics native GLP-1 incretin — slows gastric emptying, increases satiety, suppresses glucagon, improves insulin secretion. Weekly subcutaneous injection. Half-life ~7 days.

Zepbound

Tirzepatide is a dual GIP + GLP-1 receptor agonist. Activates two incretin pathways simultaneously, producing greater weight loss and glycemic improvement than GLP-1-only agonists. Weekly subcutaneous injection. Half-life ~5 days.

Available formulations

Wegovy

  • Pre-filled pen — 0.25mg / 0.5mg / 1.0mg / 1.7mg / 2.4mg (titration ladder)
  • Weekly subcutaneous injection (thigh, abdomen, upper arm)
  • Refrigerate until first use; room temperature OK up to 6 weeks after
  • FDA-approved for chronic weight management in adults with BMI ≥30 or ≥27 + comorbidity

Zepbound

  • Pre-filled pen or single-dose vial — 2.5mg / 5mg / 7.5mg / 10mg / 12.5mg / 15mg
  • Weekly subcutaneous injection (thigh, abdomen, upper arm)
  • Refrigerate until first use; room temperature OK up to 21 days after
  • FDA-approved for chronic weight management same indication as Wegovy

Who it's for

Wegovy

  • BMI ≥30 (or ≥27 + 1 comorbidity: type 2 diabetes, hypertension, dyslipidemia, OSA)
  • Patients preferring longer real-world safety record
  • Insurance-covered semaglutide access available (PA may be needed)
  • PCOS-related weight management (off-label but common practice)

Zepbound

  • Same BMI criteria as Wegovy
  • Patients wanting maximum efficacy (~6% more weight loss)
  • Patients tolerated semaglutide poorly or plateaued
  • Type 2 diabetes + obesity (Mounjaro = same molecule for diabetes)

Who should avoid

Wegovy

  • Personal or family history of medullary thyroid cancer (MTC) or MEN2
  • Pregnancy or breastfeeding
  • History of pancreatitis
  • Severe gastroparesis
  • Bulimia or active eating disorder

Zepbound

  • Same contraindications as Wegovy (MTC/MEN2, pregnancy, pancreatitis)
  • Severe renal impairment without dose adjustment
  • Patients unable to manage GI side effects

Side effects

Wegovy

  • Nausea (~44%) — most common, peaks during titration
  • Diarrhea (~30%)
  • Constipation (~24%)
  • Vomiting (~24%)
  • Injection-site reactions (~7%)
  • Pancreatitis (rare, <1% but black-box warning)
  • Gallbladder events (~2%)

Zepbound

  • Nausea (~33%)
  • Diarrhea (~22%)
  • Vomiting (~15%)
  • Constipation (~17%)
  • Decreased appetite (~11%)
  • Pancreatitis (rare)
  • Hypoglycemia (when combined with sulfonylureas/insulin)

Common questions(5)

Which is better for weight loss — Wegovy or Zepbound?

In head-to-head trials (SURMOUNT-5, NEJM 2024), tirzepatide (Zepbound) produced greater weight loss than semaglutide (Wegovy) — approximately 20.2% vs 13.7% body-weight reduction at 72 weeks. Both are FDA-approved for chronic weight management. Zepbound is currently the most effective FDA-approved obesity medication available.

Why are Mounjaro and Wegovy/Zepbound different brand names for the same molecules?

Mounjaro (tirzepatide) and Ozempic (semaglutide) are FDA-approved for type 2 diabetes. Zepbound (tirzepatide) and Wegovy (semaglutide) contain the identical molecules but at obesity-specific dosing and labeled for chronic weight management. The same drug ships under two brand names depending on the FDA indication.

Will insurance cover Wegovy or Zepbound?

Coverage varies significantly. Many commercial plans cover one but not both, often requiring prior authorization, BMI documentation, and failed lifestyle intervention. Medicare does not cover medications for weight loss alone (statutory exclusion). Cash-pay cost ranges $1,000-1,350/month. Telehealth platforms sometimes negotiate better rates via manufacturer savings programs.

What happens when I stop taking Wegovy or Zepbound?

Weight regain is common. STEP-1 extension data showed that participants regained approximately two-thirds of lost weight within one year of discontinuation. Both medications are intended for chronic, long-term use. If you discontinue, behavioral lifestyle changes are critical to maintaining weight loss. Discuss tapering strategy with your prescriber rather than stopping abruptly.

Is compounded semaglutide or tirzepatide as effective as brand-name?

Compounded versions are not FDA-approved. As of 2024, the FDA removed semaglutide and tirzepatide from the drug shortage list, meaning compounding pharmacies should no longer produce these molecules at scale. Compounded versions may vary in potency, sterility, and safety. Discuss with your prescriber before considering compounded sources.

Sources(6)

Peer-reviewed and regulatory references. External links open in new tab.