Weight lossActive ingredient
Tirzepatide
GIP and GLP-1 receptor agonist2 FDA labels read
Tirzepatide is sold under two brand names with two different approvals. Zepbound is approved for weight management and for moderate to severe obstructive sleep apnoea in adults with obesity. Mounjaro is approved for type 2 diabetes. The active ingredient is identical.
Highlights of the labels
- Zepbound
- Weight management, and obstructive sleep apnoea in obesitycovers weight loss
- Mounjaro
- Type 2 diabetesnot weight loss
- Supply
- Prescription only
- Generic
- None approved
- Boxed warning
- WARNING: RISK OF THYROID C-CELL TUMORS
FDA boxed warning
WARNING: RISK OF THYROID C-CELL TUMORS
This warning appears in the labels for Zepbound, Mounjaro. Quoted below from the Zepbound label.
- 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).
A boxed warning is the most serious warning the FDA requires. This text is reproduced from the label.
Brands and what each one is approved for
One active ingredient can hold several separate FDA approvals. They are different documents with different approved uses, and mixing them up is the most common mistake made about these medications.
| Brand | What its label approves | Supply | Label version |
|---|---|---|---|
| ZepboundEli Lilly and Company | What its label approvesWeight management, and obstructive sleep apnoea in obesityCovers weight loss | SupplyPrescription | Label version22 April 2026 |
| MounjaroEli Lilly and Company | What its label approvesType 2 diabetesNot weight loss | SupplyPrescription | Label version22 April 2026 |
How it works
Tirzepatide activates two gut hormone receptors rather than one: GIP and GLP-1. The FDA label describes effects on insulin secretion, on glucagon, on gastric emptying and on food intake. It is the only medication in this category that acts on the GIP receptor.
Mechanism of action, Zepbound label
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.
What the FDA approved it for
The approved uses, as worded in the label.
Zepbound
- 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.
Mounjaro
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
The presentations and strengths listed in the label.
Zepbound and Mounjaro
- 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 the label says it is taken
What the label states about administration. It is not a dosing instruction for any individual.
Zepbound
- 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.
Mounjaro
- 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.
Most common adverse reactions
The adverse reactions the label reports as most common.
Zepbound
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.
Mounjaro
most common adverse reactions, reported in ≥5% of patients treated with MOUNJARO are nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, and abdominal pain.
Warnings and precautions
The warnings and precautions section of the label.
Zepbound
- 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.
Mounjaro
- 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.
Contraindications
Situations in which the label states the medication must not be used.
Zepbound
- 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
Mounjaro
- 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.
Drug interactions
Interactions the label singles out.
Zepbound
ZEPBOUND delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications.
Mounjaro
MOUNJARO delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications.
Pregnancy and breastfeeding
The opening of the pregnancy section of the label. The full section is longer and is in the source document.
Zepbound
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.
Mounjaro
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.
Generic or brand
No generic tirzepatide has been approved in the United States. As with semaglutide, compounded versions are not FDA-approved products and are not described by the labels on this page.
The FDA label database lists no approved generic application for this ingredient.
What affects the cost
Both products are brand-only. Coverage frequently differs between the diabetes approval and the weight management approval, which is the practical reason the two brand names exist for one molecule. This site sells nothing and links to no sellers.
What pharmacies pay for it
These are acquisition costs: what pharmacies in the United States pay on average to buy the medication, published weekly by the Centers for Medicare and Medicaid Services. They are not retail prices and not what a person pays at the counter, which depends on insurance, pharmacy and discount programmes. They are useful as an objective floor and for seeing how far a brand sits above its generic.
| Measured | Brand |
|---|---|
| per millilitre | Brand$526.18 (range $201.23 to $542.28, 460 listings) |
Median of 460 listings. Effective dates 2025-12-17 to 2026-07-22, file dated 2026-07-29.
Compared with other medications
What the labels do not do is compare one medication against another. These pages put two of them side by side.
Common questions
- What is the difference between Mounjaro and Zepbound?
- The active ingredient is the same. The approvals are not. Zepbound is approved for chronic weight management and for obstructive sleep apnoea in adults with obesity. Mounjaro is approved to improve glycaemic control in adults with type 2 diabetes. Each has its own label, and this page links to both.
- How is tirzepatide different from semaglutide?
- Semaglutide acts on the GLP-1 receptor. Tirzepatide acts on both the GIP and the GLP-1 receptor. Beyond that, the two have separate labels, separate dose schedules and separate lists of approved uses, which are set out side by side on our comparison page.
- Does tirzepatide carry a boxed warning?
- Yes. Both labels carry a boxed warning about the risk of thyroid C-cell tumours, with the same contraindications as the other medications in this class. The text is quoted in full on this page.
Other medications under weight loss
Whether each one carries an FDA approval for this use is marked on its page and in this list.
Sources
Every fact above comes from one of these documents. The date is the effective date of the label version this page was built from.
FDA prescribing information for Zepbound
Eli Lilly and Company. Label version 38, effective 22 April 2026.
FDA prescribing information for Mounjaro
Eli Lilly and Company. Label version 38, effective 22 April 2026.
Each stripe is one section of the label, each division in a stripe one entry in that section. The red bar marks a boxed warning.
Page last updated 18 August 2026
Compiled by the HealthyStudy editorial team from FDA source documents. No medical reviewer is credited on this page, because none reviewed it.