Mounjaro vs Zepbound
Editorial comparison of Mounjaro (tirzepatide) and Zepbound (tirzepatide). Same drug class context, trial-anchored data, no marketing claims.
Side-by-side
| Dimension | Mounjaro | Zepbound |
|---|---|---|
| Generic name | tirzepatide | tirzepatide |
| Manufacturer | Eli Lilly | Eli Lilly |
| FDA approved | 2022 | 2023 |
| Mechanism | Same as Zepbound — dual GLP-1/GIP receptor agonist. Strong glycemic effect plus weight loss. | Tirzepatide is a dual incretin agonist: it hits both the GLP-1 receptor (like semaglutide) and the GIP receptor (which semaglutide doesn't). |
| Dosing | Titrated 2.5mg → 15mg weekly over months, same schedule as Zepbound. | Titrated 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg, every 4 weeks. Maintenance 5-15mg weekly depending on tolerability and target weight. |
| Cost | Similar to Zepbound — list ~$1,000/month, LillyDirect Self-Pay $399-549/month. | List price ~$1,000-1,300/month. |
| Pivotal trial result | 2.0–2.3% HbA1c reduction across SURPASS trials (15 mg dose) | 20.9% mean body-weight reduction at 72 weeks (15 mg dose) |
Efficacy in the trials
2.0–2.3% HbA1c reduction across SURPASS trials (15 mg dose)
SURPASS-2 (NCT03987919) — vs semaglutide · Tirzepatide 15 mg achieved 2.30% HbA1c reduction vs 1.86% for semaglutide 1 mg · n=1,879
20.9% mean body-weight reduction at 72 weeks (15 mg dose)
SURMOUNT-1 (NCT04184622) · vs 3.1% with placebo · n=2,539
Trial averages describe study populations, not individuals. Response varies with the dose tolerated, adherence, and personal physiology; the two drugs were not necessarily tested head-to-head in the same trial.
The details
Dosing & cadence
Cost & access
Side effects
Which should you choose?
If maximizing average trial weight loss is the priority, Zepbound posted the higher pivotal-trial figure; Mounjaro still produced clinically meaningful loss and some people tolerate it better. On cost and access, compare each drug's manufacturer direct-pay and insurance path — that often matters more month-to-month than the efficacy gap. Both carry class safety considerations (see each drug's boxed-warning and contraindications); a personal or family history of medullary thyroid carcinoma or MEN2 rules out the GLP-1 class. Bring this comparison to a prescriber, who will match the drug to your history and titrate the dose.
This is editorial framing, not a prescription. The right choice depends on your medical history, insurance, and a clinician's evaluation.
Full Mounjaro review →
FDA-approved tirzepatide for type 2 diabetes. Off-label for weight loss is common.
Full Zepbound review →
Dual GLP-1/GIP agonist for weight management. ~20% body weight loss in trials — strongest weight-loss drug currently available.
Deciding at the molecule level? Semaglutide vs Tirzepatide compares the two drug families behind every major GLP-1 brand.
Frequently asked
Is Mounjaro or Zepbound more effective?+
In their pivotal trials, Mounjaro reported 2.0–2.3% HbA1c reduction across SURPASS trials (15 mg dose), while Zepbound reported 20.9% mean body-weight reduction at 72 weeks (15 mg dose). Head-to-head results vary by patient profile, dose tolerated, and adherence — these trial numbers describe averages, not what every individual experiences.
How do Mounjaro and Zepbound compare on cost?+
Mounjaro: Similar to Zepbound — list ~$1,000/month, LillyDirect Self-Pay $399-549/month. Zepbound: List price ~$1,000-1,300/month. Lilly's patient assistance program (LillyDirect Self-Pay) offers $399-549/month for self-pay patients depending on dose. Insurance coverage similar pattern to Wegovy. Real out-of-pocket depends on insurance formulary tier, manufacturer savings programs, and whether a direct-pay channel is available.
Can I switch from Mounjaro to Zepbound?+
Switching between brand-name treatments in the same drug class is common, but the conversion is not always 1:1. Discuss the switch with your prescriber — they'll usually re-titrate dosing rather than substitute equivalent strengths directly.
Are Mounjaro and Zepbound the same drug?+
No. Mounjaro (tirzepatide) and Zepbound (tirzepatide) are distinct medications from Eli Lilly and Eli Lilly respectively. They may share a drug class or mechanism but differ in active ingredient, dosing, and approved use.