Mounjaro vs Ozempic: Tirzepatide vs Semaglutide, Brand by Brand

Mounjaro is Tirzepatide (Eli Lilly). Ozempic is Semaglutide (Novo Nordisk). Different molecules, different mechanisms — Mounjaro is GIP + GLP-1 dual agonism; Ozempic is GLP-1 monoagonism. In head-to-head trials Mounjaro produces meaningfully larger weight loss at comparable T2D efficacy. Both are FDA-approved for type 2 diabetes; their respective weight-loss brand siblings are Zepbound and Wegovy. This article covers the brand-level comparison plus the practical differences in insurance, pen format, and side-effect tolerability.

For the deeper molecule-vs-molecule comparison, see Semaglutide vs Tirzepatide. For the within-brand sibling comparisons, see Ozempic vs Wegovy.

Quick verdict table

	Mounjaro	Ozempic
Active drug	Tirzepatide	Semaglutide
Manufacturer	Eli Lilly	Novo Nordisk
Mechanism	GIP + GLP-1 dual agonist	GLP-1 monoagonist
FDA indication	Type 2 diabetes	Type 2 diabetes (+ CV risk reduction in T2D + CVD)
Weight-loss sibling brand	Zepbound	Wegovy
Maximum T2D dose	15 mg weekly	2 mg weekly
Trial weight loss (T2D, SURPASS-2 head-to-head)	~12% at 40 weeks	~6% at 40 weeks
Pen format	Single-use auto-injector at each dose	Multi-dose pen with dial
CV outcome data	SURPASS-CVOT reads 2026–2027	LEADER / SUSTAIN / SELECT
List price (US, T2D)	~$1,000–$1,300/month	~$900–$1,200/month

What the mechanisms actually do differently

Ozempic (Semaglutide) binds the GLP-1 receptor only. The downstream effects: slowed gastric emptying, central appetite suppression, glucose-dependent insulin release.

Mounjaro (Tirzepatide) binds both the GLP-1 receptor and the GIP receptor. GIP on its own doesn't reliably produce weight loss in trials, but the combination with GLP-1 is synergistic — larger weight loss and somewhat better tolerability at matched-efficacy doses.

Head-to-head trial data

SURPASS-2 was the published head-to-head in T2D patients:

• At 40 weeks, Tirzepatide 15 mg weekly produced ~12% weight loss and ~2.3% A1C reduction.
• At the same timepoint, Semaglutide 1 mg weekly produced ~6% weight loss and ~1.9% A1C reduction.

Tirzepatide wins on both endpoints by a meaningful margin. Note that Semaglutide's maximum T2D dose in SURPASS-2 was 1 mg; Ozempic later got 2 mg approval, which narrows but does not eliminate the gap.

Side effects

Both drugs share the same GI-dominated side-effect profile: nausea, vomiting, diarrhea, constipation. Two notable differences:

• Tolerability at matched efficacy. In real-world practice, Tirzepatide is often described as somewhat better tolerated at the dose required to produce equivalent weight loss to Semaglutide.
• Discontinuation rates. In head-to-head trials, discontinuation due to GI side effects was broadly similar between the two. At maximum doses for each, profiles are comparable.

Both carry the boxed warning for thyroid C-cell tumors (rodent finding; human signal not established) and contraindicate patients with personal or family history of medullary thyroid carcinoma or MEN2.

See peptide side effects.

Insurance + access

• Ozempic is broadly covered for T2D. Supply has normalized since the 2022–2024 shortage; specific doses may still be intermittent.
• Mounjaro is covered for T2D under most major plans; supply has been more constrained but is normalizing through 2026.
• Wegovy (Semaglutide for weight loss) has expanded coverage on more plans; Zepbound (Tirzepatide for weight loss) has caught up rapidly through 2025–2026.
• Manufacturer savings cards (Novo's WeGoTogether, Lilly's Zepbound savings card) reduce cash-pay sticker meaningfully for eligible patients.

See peptide therapy cost for the full pricing breakdown.

How to choose

• Type 2 diabetes is the primary indication? Either works. Mounjaro produces somewhat larger A1C reduction; both have strong T2D data.
• You also want maximum weight loss? Mounjaro / Zepbound.
• You have established cardiovascular disease? Semaglutide / Ozempic has the documented MACE benefit (SELECT). Tirzepatide's SURPASS-CVOT reads 2026–2027.
• Cost / insurance is the binding constraint? Whichever your insurance covers better.
• Pen-format preference? Ozempic's multi-dose pen is more convenient for users staying at a stable dose; Mounjaro's single-use auto-injectors at each strength are simpler to track during titration.

Both have brand siblings for weight loss

If the primary goal is weight loss in a patient who doesn't have T2D, the on-label brand is the sibling:

• Wegovy for Semaglutide weight-loss use (BMI ≥ 30 or ≥ 27 + comorbidity).
• Zepbound for Tirzepatide weight-loss use (same BMI criteria).

See Ozempic vs Wegovy for the same-drug brand-siblings discussion.

Bottom line

• Mounjaro and Ozempic are different molecules, not different brands of the same thing.
• Mounjaro produces larger weight loss in head-to-head trials.
• Ozempic has documented cardiovascular benefit (SELECT) that Mounjaro is still proving in SURPASS-CVOT.
• Coverage and supply now broadly similar.
• For weight loss specifically, use the weight-loss siblings (Zepbound or Wegovy).

Where to go from here

• Semaglutide vs Tirzepatide — deeper molecule comparison.
• Ozempic vs Wegovy — Semaglutide brand siblings.
• Tirzepatide vs Retatrutide — next-gen contender.
• Peptides for weight loss — pillar.
• Best peptides for fat loss — ranked roundup.
• Per-peptide profiles: Semaglutide, Tirzepatide.
• Are peptides safe?, peptide side effects, peptide therapy — safety frame.

This is informational, not medical advice.