They are different molecules
Wegovy is semaglutide — a GLP-1 receptor agonist. Single mechanism: GLP-1 receptor activation in gut, brain, and pancreas. Approved for chronic weight management at the 2.4 mg dose since June 2021.
Zepbound is tirzepatide — a dual GLP-1/GIP agonist. Activates both GLP-1 receptors AND GIP receptors. Approved for chronic weight management at the 15 mg dose since November 2023.
The molecular difference (single vs dual agonism) is the basis for the efficacy gap. GIP activation adds effects on adipose tissue function and fat oxidation that GLP-1 alone does not provide.
SURMOUNT-5: the only head-to-head trial
Published in NEJM 2024. 751 adults with BMI ≥30, randomized to tirzepatide 15 mg or semaglutide 2.4 mg, 72 weeks of treatment.
Headline result: tirzepatide 20.2% mean weight loss vs semaglutide 13.7%. Relative advantage 47%. Achieved ≥15% loss: 64% on tirzepatide, 40% on semaglutide. Discontinuation due to adverse events: 10.4% vs 7.6%.
Translation: tirzepatide produced meaningfully more weight loss with slightly higher dropout. For patients who tolerate either drug, tirzepatide is the higher-efficacy choice.
Each drug's unique strengths
Wegovy advantages: cardiovascular outcome data (SELECT trial showed 20% MACE reduction in adults with established CV disease + overweight/obesity), older safety profile (more years on market), wider provider familiarity. If you have cardiovascular disease or want the more-established drug, Wegovy.
Zepbound advantages: FDA approval for moderate-severe sleep apnea (December 2024) — only GLP-1 with this indication. Higher weight loss efficacy. Earlier titration tolerability for many patients. If you have OSA or want maximum loss, Zepbound.
Cost and insurance coverage
List prices: Wegovy ~$1,350/month, Zepbound ~$1,060/month. Both qualify for manufacturer savings cards that bring commercial-insured price to ~$499/month.
Insurance coverage typically requires BMI ≥30 or BMI ≥27 with comorbidity. Sleep apnea diagnosis specifically improves Zepbound coverage approval. Established cardiovascular disease specifically improves Wegovy coverage.
Medicare GLP-1 Bridge (July 1, 2026) covers both at $50/mo copay.
Who should pick which
Pick Wegovy if: you have established CV disease, your insurance covers it preferentially, you want the more-established drug, or you had good results on Ozempic previously.
Pick Zepbound if: you have moderate-severe sleep apnea, you want maximum weight loss efficacy, your insurance covers it preferentially, or you had insufficient results on a GLP-1-only drug.
If both are accessible at similar cost: most clinicians now suggest Zepbound first-line for adults without contraindications.
Frequently asked questions
- Is Zepbound stronger than Wegovy?
- Yes — SURMOUNT-5 showed 47% greater relative weight loss with Zepbound at 72 weeks (20.2% vs 13.7%).
- Can I switch from Wegovy to Zepbound?
- Yes. Discuss with your prescriber. Standard approach: take last Wegovy dose, wait 7 days, start Zepbound at clinically-equivalent dose. See our dose conversion tool.
- Does insurance cover Wegovy or Zepbound?
- Coverage varies. Both require BMI ≥30 or BMI �≥27 + comorbidity + prior authorization. Plans that cover one may not cover the other — check your formulary.
- Is Wegovy or Zepbound better for sleep apnea?
- Zepbound — it is the only GLP-1 FDA-approved for moderate-severe OSA (December 2024). Wegovy reduces AHI through weight loss but does not have OSA-specific FDA indication.
- Which is cheaper, Wegovy or Zepbound?
- Zepbound list price (~$1,060/mo) is somewhat lower than Wegovy (~$1,350/mo). With manufacturer savings cards, both commercially-insured patients pay around $499/mo.
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