Ozempic vs Mounjaro
GLP-1 Single Agonist vs GIP+GLP-1 Dual Agonist for Type 2 Diabetes
Ozempic (semaglutide 0.5–2 mg weekly) and Mounjaro (tirzepatide 2.5–15 mg weekly) are both injectable GLP-1 receptor agonists approved for type 2 diabetes — but Mounjaro adds GIP receptor activation, giving it a dual mechanism. The SURPASS-2 trial directly compared 1 mg semaglutide against tirzepatide and found tirzepatide superior on both HbA1c reduction and weight loss. Track either drug in Shotlee to measure your personal response.
Mechanism of Action
- →GLP-1 receptor agonist only
- →Stimulates insulin secretion in a glucose-dependent manner
- →Suppresses glucagon release to reduce hepatic glucose output
- →Acts on hypothalamus to reduce appetite and food intake
- →Slows gastric emptying, prolonging satiety signals
- →Half-life ~7 days; once-weekly subcutaneous injection
- →Approved for T2D (Ozempic) and obesity at higher dose (Wegovy 2.4 mg)
- →Dual GIP + GLP-1 receptor agonist (novel dual incretin)
- →GIP agonism enhances adipose insulin sensitivity
- →GIP co-activation may blunt GLP-1-driven nausea
- →Deeper HbA1c and weight reduction vs GLP-1 monotherapy in trials
- →Also suppresses appetite via hypothalamic and vagal pathways
- →Half-life ~5 days; once-weekly subcutaneous injection
- →Approved for T2D (Mounjaro) and obesity (Zepbound)
Head-to-Head Comparison
| Factor | Ozempic | Mounjaro |
|---|---|---|
| Active molecule | Semaglutide | TirzepatideBest |
| Receptor targets | GLP-1 only | GIP + GLP-1 |
| T2D dose range | 0.5 mg, 1 mg, 2 mg weekly | 2.5–15 mg weekly |
| HbA1c reduction (SURPASS-2) | −1.9% (1 mg sema) | −2.3% (tirzepatide 15 mg) |
| Weight loss (SURPASS-2) | −5.3 kg (1 mg sema) | −11.2 kg (tirzepatide 15 mg) |
| Nausea incidence | ~15–20% at T2D doses | ~12–18% at T2D doses |
| CV outcome trial | SUSTAIN-6 + SELECT (positive) | SURPASS-CVOT 2024: 15% MACE reduction |
| Obesity-approved brand | Wegovy (2.4 mg) | Zepbound (15 mg) |
| Oral formulation | Yes — Rybelsus (T2D only) | In development |
| Compounded available | Check FDA shortage list | Limited — check FDA status |
Key Numbers from SURPASS-2
Choose Based on Your Goal
Maximum HbA1c reduction
Tirzepatide 15 mg achieved −2.3% HbA1c vs −1.9% for semaglutide 1 mg in SURPASS-2. Tirzepatide leads on glycaemic control.
Weight loss alongside T2D
Tirzepatide 15 mg: −11.2 kg vs −5.3 kg for semaglutide 1 mg in SURPASS-2. Dual agonism drives significantly more weight reduction.
Longer cardiovascular data
Ozempic has SUSTAIN-6 (2016) and SELECT (2023) with published long-term MACE data. SURPASS-CVOT for tirzepatide published 2024.
GI tolerability
Both cause nausea, vomiting, and diarrhoea at similar rates at T2D doses. Mounjaro may have slightly lower nausea due to GIP modulation.
Oral option preferred
If you prefer an oral medication, Rybelsus (oral semaglutide 3–14 mg) is available for T2D. No oral tirzepatide is approved yet.
Insurance and cost
Both are similarly priced at ~$900–1,100/month uninsured. T2D coverage for both is generally stronger than obesity coverage.
Which Is Right for You?
The SURPASS-2 trial is the landmark direct comparison: tirzepatide at all three doses (5, 10, 15 mg) beat semaglutide 1 mg on HbA1c reduction and weight loss. For patients with type 2 diabetes where both HbA1c control and weight management are priorities, tirzepatide offers a measurable advantage per the trial data.
Ozempic has a longer track record. SUSTAIN-6 (2016) established cardiovascular benefit in T2D, and SELECT (2023) showed a 20% MACE reduction in people with obesity without diabetes. Semaglutide also has an oral formulation (Rybelsus) and a well-established prescribing history since 2017.
Both drugs require slow dose escalation to minimise GI side effects and are contraindicated in patients with personal or family history of medullary thyroid carcinoma. Talk with your endocrinologist about which best fits your full metabolic and cardiovascular profile.
Ozempic vs Mounjaro: Frequently Asked Questions
Yes. SURPASS-2 (Frias et al., NEJM 2021) directly compared tirzepatide (5, 10, 15 mg) against semaglutide 1 mg in adults with type 2 diabetes over 40 weeks. All three tirzepatide doses were superior to semaglutide 1 mg on both HbA1c reduction and weight loss.
By trial data, yes. In SURPASS-2, tirzepatide 15 mg produced −11.2 kg weight loss vs −5.3 kg for semaglutide 1 mg. The higher obesity doses of semaglutide (2.4 mg, Wegovy) produce more weight loss, but that is a different formulation from Ozempic.
Yes. The SURPASS-CVOT trial, published in 2024, showed a 15% reduction in MACE with tirzepatide vs placebo in people with T2D and established cardiovascular disease. Ozempic's SUSTAIN-6 and SELECT trials also showed positive cardiovascular outcomes.
Yes, with prescriber guidance. No mandatory washout is required. Standard practice is to start tirzepatide at 2.5 mg and escalate normally regardless of prior semaglutide dose. Track both in Shotlee to monitor the transition.
Both are generally covered for type 2 diabetes treatment. Coverage for weight loss without T2D is more variable. Manufacturer savings cards from Novo Nordisk (Ozempic) and Eli Lilly (Mounjaro) can reduce out-of-pocket costs for eligible patients.
Track Ozempic or Mounjaro in Shotlee
Log doses, weight, HbA1c, and side effects for either drug. Free for iOS and Android.
📚References & sources
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