Is tirzepatide better than semaglutide?

Neither label makes a comparative claim, and the honest position is that comparing them is a clinical judgement rather than something a reference page can settle.

Why does Europe use one brand name for both uses?

Because the European authorisation covers both indications under the name Mounjaro, while the United States approved them separately under two names. Same substance either way.

What is the boxed warning about?

It concerns thyroid tumours seen in animal studies, and it appears in full in the label section above. It is also the reason the contraindications list specific family histories.

Tirzepatide

The newer injection, acting on two gut hormone receptors instead of one, and sold as Zepbound for weight and Mounjaro for diabetes.

Class: GIP and GLP-1 receptor agonist
Sold as: Sold as: Zepbound, Mounjaro; Prescription only

Boxed warning

WARNING: RISK OF THYROID C-CELL TUMORS

In rats, tirzepatide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures. It is unknown whether ZEPBOUND causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined. ZEPBOUND is contraindicated in patients with a personal or family history of MTC or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Counsel patients regarding the potential risk for MTC with the use of ZEPBOUND and inform them of symptoms of thyroid tumors (e.g., a mass in the neck, dysphagia, dyspnea, persistent hoarseness).

From the approved label

Zepbound

Approved uses: ZEPBOUND is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist indicated in combination with a reduced-calorie diet and increased physical activity: to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition.
to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity.
Limitations of Use: Coadministration with other tirzepatide-containing products or with any GLP-1 receptor agonist is not recommended.
Forms and strengths: Injection: Clear, colorless to slightly yellow solution in pre-filled single-dose pens, single-dose vials, multi-dose vials, or single-patient-use KwikPens, each available in the following strengths.
The multi-dose vials and single-patient-use KwikPen each contain 4 doses: Single-dose Pen or Vial 2.5 mg/0.5 mL 5 mg/0.5 mL 7.5 mg/0.5 mL 10 mg/0.5 mL 12.5 mg/0.5 mL 15 mg/0.5 mL Multi-dose Vial (4...
How it is taken: Recommended Dose Escalation Schedule The recommended starting dosage is 2.5 mg injected subcutaneously once weekly for 4 weeks. Increase the dosage in 2.5 mg increments after at least 4 weeks until recommended maintenance dosage is achieved.
Consider treatment response and tolerability when selecting the maintenance dosage.
Recommended Maintenance and Maximum Dosage Weight Reduction and Long-Term Maintenance: 5 mg, 10 mg, or 15 mg injected subcutaneously once weekly.
Obstructive Sleep Apnea: 10 mg or 15 mg injected subcutaneously once weekly.
Maximum Recommended Dosage: 15 mg injected subcutaneously once weekly.
Administration Instructions Refer to the Full Prescribing Information for additional important administration instructions about ZEPBOUND presentations.
Must not be used when: ZEPBOUND is contraindicated in patients with: A personal or family history of MTC or in patients with MEN 2.
Known serious hypersensitivity to tirzepatide or any of the excipients in ZEPBOUND.
Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported with tirzepatide.
Personal or family history of medullary thyroid carcinoma or in patients with Multiple Endocrine Neoplasia syndrome type 2 Known serious hypersensitivity to tirzepatide or any of the excipients in ZEPBOUND
Interactions: ZEPBOUND delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications.
Warnings and precautions: Severe Gastrointestinal Adverse Reactions: Use has been associated with gastrointestinal adverse reactions, sometimes severe. ZEPBOUND is not recommended in patients with severe gastroparesis.
Acute Kidney Injury Due to Volume Depletion: Monitor renal function in patients reporting adverse reactions that could lead to volume depletion.
Acute Gallbladder Disease: Has been reported in clinical trials. If cholecystitis is suspected, gallbladder studies and clinical follow-up are indicated.
Acute Pancreatitis: Has been observed in patients treated with GLP-1 receptor agonists, or ZEPBOUND. Discontinue if pancreatitis is suspected.
Hypersensitivity Reactions: Serious hypersensitivity reactions (e.g., anaphylaxis, angioedema) have been reported postmarketing with tirzepatide. If suspected, advise patients to promptly seek medical attention and discontinue ZEPBOUND.
Hypoglycemia: Concomitant use with insulin or an insulin secretagogue may increase the risk of hypoglycemia, including severe hypoglycemia. Reducing dose of insulin or insulin secretagogue may be necessary. Inform all patients of the risk of hypoglycemia and educate them on the signs and symptoms of hypoglycemia.
Diabetic Retinopathy Complications in Patients with Type 2 Diabetes Mellitus: Has not been studied in patients with non-proliferative diabetic retinopathy requiring acute therapy, proliferative diabetic retinopathy, or diabetic macular edema. Monitor patients with a history of diabetic retinopathy for progression.
Pulmonary Aspiration During General Anesthesia or Deep Sedation: Has been reported in patients receiving GLP-1 receptor agonists undergoing elective surgeries or procedures. Instruct patients to inform healthcare providers of any planned surgeries or procedures.
Common side effects: most common adverse reactions, reported in ≥5% of patients treated with ZEPBOUND are: nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, injection site reactions, fatigue, hypersensitivity reactions, eructation, hair loss, gastroesophageal reflux disease.
Pregnancy: Pregnancy Exposure Registry There will be a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ZEPBOUND (tirzepatide) during pregnancy. Pregnant patients exposed to ZEPBOUND and healthcare providers are encouraged to contact Eli Lilly and Company at 1-800-LillyRx (1-800-545-5979). Risk Summary Weight loss offers no benefit to a pregnant patient and may cause fetal harm.
How it acts: Tirzepatide is a GIP receptor and GLP-1 receptor agonist. It contains a C20 fatty diacid that enables albumin binding and prolongs the half-life. Tirzepatide selectively binds to and activates both the GIP and GLP-1 receptors, the targets for native GIP and GLP-1.

Label holder:: Eli Lilly and Company
Label version:: 22 April 2026

This section reports the approved product information. The wording is condensed from the regulator's own summary, and the full document is linked under Sources.

Written by us

How it works

Tirzepatide acts on the receptor semaglutide acts on and on a second one as well. Both are receptors for hormones the gut releases when food arrives, and the practical effect is the same in kind: slower stomach emptying, earlier fullness, lower appetite. Whether acting on two receptors rather than one produces a different result is a question the labels do not answer and this page will not either.

Original and generic

No generic exists and none can until the patents expire. In Europe the brand Mounjaro carries both the diabetes and the weight indication under a single European authorisation, which is a difference from the United States worth knowing when reading American sources.

What it costs

Priced per month at a level comparable to semaglutide, with the same picture on reimbursement: covered under conditions in some countries, entirely private in others.

How to get it legally

Prescription only, injected weekly. In Europe an online clinic can legitimately prescribe it, and the consultation should involve real numbers rather than a checkbox: the label states the body mass index thresholds that make the prescription appropriate.

From the approved label

Mounjaro: approved for

Approved uses: MOUNJARO ® is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus.
Forms and strengths: Injection: Clear, colorless to slightly yellow solution in pre-filled single-dose pens, single-dose vials, multi-dose vials, or single-patient-use KwikPens, each available in the following strengths.
The multi-dose vials and single-patient-use KwikPen each contain 4 doses: Single-dose Pen or Vial 2.5 mg/0.5 mL 5 mg/0.5 mL 7.5 mg/0.5 mL 10 mg/0.5 mL 12.5 mg/0.5 mL 15 mg/0.5 mL Multi-dose Vial (4...
How it is taken: The recommended starting dosage is 2.5 mg injected subcutaneously once weekly.
After 4 weeks, increase to 5 mg injected subcutaneously once weekly.
If additional glycemic control is needed, increase the dosage in 2.5 mg increments after at least 4 weeks on the current dose.
Maximum dosage: Adults: 15 mg subcutaneously once weekly. Pediatric patients 10 years of age and older: 10 mg subcutaneously once weekly. Administer once weekly at any time of day, with or without meals.
Inject subcutaneously in the abdomen, thigh, or another person should inject in the back of the upper arm. Rotate injection sites with each dose.
Refer to the Full Prescribing Information for additional important administration instructions about MOUNJARO presentations.
Must not be used when: MOUNJARO is contraindicated in patients with: A personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Known serious hypersensitivity to tirzepatide or any of the excipients in MOUNJARO.
Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported with MOUNJARO.
Interactions: MOUNJARO delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications.
Warnings and precautions: Acute Pancreatitis: Has been observed in patients treated with GLP-1 receptor agonists, or MOUNJARO. Discontinue if pancreatitis is suspected.
Hypoglycemia with Concomitant Use of Insulin Secretagogues or Insulin: Concomitant use with an insulin secretagogue or insulin may increase the risk of hypoglycemia, including severe hypoglycemia. Reducing dose of insulin secretagogue or insulin may be necessary.
Hypersensitivity Reactions: Serious hypersensitivity reactions (e.g., anaphylaxis and angioedema) have been reported. Discontinue MOUNJARO if suspected and promptly seek medical advice.
Acute Kidney Injury Due to Volume Depletion: Monitor renal function in patients reporting adverse reactions that could lead to volume depletion.
Severe Gastrointestinal Adverse Reactions: Use has been associated with gastrointestinal adverse reactions, sometimes severe. MOUNJARO is not recommended in patients with severe gastroparesis.
Diabetic Retinopathy Complications in Patients with a History of Diabetic Retinopathy: Has not been studied in patients with non-proliferative diabetic retinopathy requiring acute therapy, proliferative diabetic retinopathy, or diabetic macular edema. Monitor patients with a history of diabetic retinopathy for progression.
Acute Gallbladder Disease: Has occurred in clinical trials. If cholelithiasis is suspected, gallbladder studies and clinical follow-up are indicated.
Pulmonary Aspiration During General Anesthesia or Deep Sedation: Has been reported in patients receiving GLP-1 receptor agonists undergoing elective surgeries or procedures. Instruct patients to inform healthcare providers of any planned surgeries or procedures.
Common side effects: most common adverse reactions, reported in ≥5% of patients treated with MOUNJARO are nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, and abdominal pain.
Pregnancy: Available data with MOUNJARO use in pregnant women are insufficient to evaluate for a drug-related risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy (see Clinical Considerations). Based on animal reproduction studies, there may be risks to the fetus from exposure to tirzepatide during pregnancy.
How it acts: Tirzepatide is a GIP receptor and GLP-1 receptor agonist. It contains a C20 fatty diacid that enables albumin binding and prolongs the half-life. Tirzepatide selectively binds to and activates both the GIP and GLP-1 receptors, the targets for native GIP and GLP-1.

Label holder:: Eli Lilly and Company
Label version:: 22 April 2026

This section reports the approved product information. The wording is condensed from the regulator's own summary, and the full document is linked under Sources.

Comparison

Questions

Is tirzepatide better than semaglutide?: Neither label makes a comparative claim, and the honest position is that comparing them is a clinical judgement rather than something a reference page can settle.
Why does Europe use one brand name for both uses?: Because the European authorisation covers both indications under the name Mounjaro, while the United States approved them separately under two names. Same substance either way.
What is the boxed warning about?: It concerns thyroid tumours seen in animal studies, and it appears in full in the label section above. It is also the reason the contraindications list specific family histories.

Sources

Zepbound, ZEPBOUND, Zepbound KwikPen: prescribing informationDailyMed, US National Library of Medicine. Label version 22 April 2026
Mounjaro, Mounjaro KwikPen: prescribing informationDailyMed, US National Library of Medicine. Label version 22 April 2026
Drugs@FDA: NDA217806US Food and Drug Administration
Drugs@FDA: NDA215866US Food and Drug Administration
Mounjaro: EPAR product informationEuropean Medicines Agency