Compounds / Tirzepatide
Tirzepatide
Also known as: LY3298176, twincretin (dual GIP/GLP-1 agonist), CAS 2023788-19-2
Primary research focus: Type 2 diabetes, chronic weight management, and obstructive sleep apnea (metabolic)
Last updated July 2026 · Reviewed against FDA labeling and published research.
What is Tirzepatide?
Tirzepatide is a once-weekly injectable peptide that activates both the GIP and GLP-1 receptors (a dual incretin agonist, sometimes called a twincretin). It is marketed as Mounjaro for type 2 diabetes and as Zepbound for chronic weight management and obstructive sleep apnea. It lowers blood glucose, slows gastric emptying, and reduces appetite and food intake.
Dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor. GLP-1 receptor activation increases glucose-dependent insulin secretion, suppresses glucagon, and slows gastric emptying; GIP receptor activation is thought to add complementary effects on insulin secretion and energy metabolism. The combined effect reduces appetite and food intake and improves glycemic control. A C20 fatty diacid side chain binds serum albumin and extends the half-life, allowing once-weekly dosing.
How it’s supplied
Brand / trade names: Mounjaro, Zepbound
Marketed by Eli Lilly as Mounjaro (type 2 diabetes) and Zepbound (chronic weight management and obstructive sleep apnea). Supplied as a clear, colorless to slightly yellow solution in single-dose prefilled pens, single-dose vials, multi-dose vials, and single-patient-use KwikPens, in strengths of 2.5, 5, 7.5, 10, 12.5, and 15 mg. Approved products are supplied ready to use and are not reconstituted by the patient. Broad compounded tirzepatide is no longer generally available after the FDA resolved the shortage (see US regulatory status).
Dosage Chart
Units shown are for a U-100 insulin syringe (100 units = 1 mL), calculated from the vial size and BAC water you select. Always confirm against your prescription and your syringe markings.
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Weeks 1-4 | 2.5mg | 1x Weekly | — |
| Weeks 5-8 | 5mg | 1x Weekly | — |
| Weeks 9-12 | 7.5mg | 1x Weekly | — |
| Weeks 13-16 | 10mg | 1x Weekly | — |
| Weeks 17-20 | 12.5mg | 1x Weekly | — |
| Weeks 21+ | 15mg | 1x Weekly | — |
- Administer on the same day each week to maintain stable plasma levels
- Titrate slowly; gastrointestinal effects are dose-related and ease with gradual escalation
- Rotate injection sites to reduce irritation and lipohypertrophy
- Reduce dose when combined with insulin or sulfonylureas to lower hypoglycemia risk
- Discuss pausing before scheduled surgery or anesthesia (delayed gastric emptying)
- Maintain hydration to offset gastrointestinal fluid loss
- Not for use during pregnancy or breastfeeding
- Do not exceed the recommended dose to try to speed results
Potential Benefits and Side Effects
Effects reported in published research. Not a promise of results, and not medical advice.
- Improved glycemic control (HbA1c reduction) in type 2 diabetes.
- Significant weight reduction in obesity and overweight trials (SURMOUNT-1 and SURMOUNT-2).
- Reduction in the apnea-hypopnea index in obesity-related obstructive sleep apnea (SURMOUNT-OSA).
- Reported improvements in blood pressure and lipid parameters in trials.
- Reduction in heart failure events reported in HFpEF patients in the SUMMIT trial.
- Nausea.
- Diarrhea.
- Vomiting.
- Constipation.
- Decreased appetite.
- Dyspepsia and abdominal pain.
- Injection-site reactions.
- Hypersensitivity reactions (less common).
- Gastrointestinal effects are most common during dose escalation.
Warnings and contraindications
Important safety information. This is not exhaustive — read the full prescribing information and consult your prescriber or pharmacist.
- Boxed warning: risk of thyroid C-cell tumors. Tirzepatide caused dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and carcinomas) in rats; human relevance is unknown.
- Pancreatitis: acute pancreatitis has been reported; discontinue if suspected.
- Acute gallbladder disease (cholelithiasis, cholecystitis) has been reported; evaluate if suspected.
- Hypoglycemia: increased risk when used with insulin or insulin secretagogues (e.g., sulfonylureas); a dose reduction of the concomitant agent may be needed.
- Acute kidney injury: reported, usually in the setting of dehydration from nausea, vomiting, or diarrhea.
- Diabetic retinopathy complications may occur in patients with type 2 diabetes; monitor as clinically indicated.
- Hypersensitivity reactions, including anaphylaxis and angioedema, have been reported; discontinue if they occur.
- Severe gastrointestinal disease: not studied in patients with severe gastroparesis; use caution.
- Suicidal behavior and ideation: monitor for depression or suicidal thoughts (labeled precaution for the weight-management indication).
- Pregnancy: may cause fetal harm based on animal data.
- Do not use with other tirzepatide-containing products or any other GLP-1 receptor agonist.
- Personal or family history of medullary thyroid carcinoma (MTC).
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
- Known serious hypersensitivity to tirzepatide or any excipient in the product.
- Pregnancy and breastfeeding are contraindicated under some international labeling (e.g., Health Canada); US labeling frames pregnancy as may cause fetal harm and advises against use.
Reconstitution Steps
How to prepare the lyophilized vial. Confirm specifics with your pharmacist or prescriber.
- Confirm the vial strength on the label and the diluent volume specified by your pharmacy or prescription before starting.
- Wash your hands and gather supplies: the powder vial, the prescribed diluent (typically bacteriostatic water), an alcohol swab, and a sterile syringe.
- Let the powder vial and diluent reach room temperature if they were refrigerated.
- Wipe the rubber stopper of both the powder vial and the diluent vial with a fresh alcohol swab and let them air dry.
- Draw the exact diluent volume specified by your pharmacy into the syringe.
- Insert the needle into the powder vial and slowly release the diluent down the inside wall of the vial rather than directly onto the powder.
- Do not shake. Gently swirl or roll the vial until the powder is fully dissolved.
- Inspect the solution: it should be clear and colorless to slightly yellow with no visible particles. Do not use if cloudy, discolored, or containing particles.
- Note the resulting concentration (vial strength divided by the diluent volume) so it matches the reconstitution calculator on this page.
- Label the vial with the reconstitution date and store as directed under reconstituted storage.
US regulatory status
Classifications are public record but can change. For reference only, not legal advice.
Development: FDA approved as Mounjaro for type 2 diabetes in May 2022 (NDA 215866) and as Zepbound for chronic weight management in November 2023; Zepbound was additionally approved for moderate-to-severe obstructive sleep apnea in adults with obesity in December 2024. In July 2026 Health Canada authorized pediatric (ages 10 to 17) type 2 diabetes use based on SURPASS-PEDS. Tirzepatide does not carry an FDA cardiovascular risk-reduction indication as of mid-2026; the SURPASS-CVOT outcomes trial is expected to read out around late 2026 to early 2027. It is also being studied for additional conditions including heart failure with preserved ejection fraction (SUMMIT) and metabolic liver disease. Development code LY3298176.
Notes: The FDA determined the tirzepatide shortage resolved in late 2024. Enforcement discretion for 503A state-licensed pharmacies ended February 18, 2025, and for 503B outsourcing facilities on March 19, 2025, after courts declined to enjoin the FDA (preliminary injunction denied March 5, 2025; determination upheld May 7, 2025; on appeal to the Fifth Circuit). Tirzepatide is not on FDA's drug shortage list or the 503B bulks list, so routine essentially-a-copy compounding is not permitted. A narrow 503A pathway remains only for an individual patient with a valid prescription and a documented clinical need the commercial product cannot meet (for example an excipient allergy); cost savings alone do not qualify. Personalized combination products (e.g., tirzepatide plus B12) marketed as legally distinct remain contested. The FDA has an open proposed rule (public comment period through June 29, 2026) that would bar 503B bulk compounding of tirzepatide.
International status
Pharmacokinetics
Storage and handling
Important Notes
Practical considerations for consistency and safety.
- Mounjaro and Zepbound contain the same molecule; the brand determines the FDA-approved indication, not the drug.
- Rotate injection sites (abdomen, thigh, or upper arm) with each dose.
- Not a substitute for insulin; tirzepatide has not been studied in type 1 diabetes and should not be used in that population.
- Compounded or research-grade tirzepatide is not the FDA-approved finished drug and has not undergone FDA review for safety, potency, or sterility.
Lifestyle Factors
- Approved for use together with a reduced-calorie diet and increased physical activity for weight management.
- Adequate hydration can reduce the risk of dehydration-related complications during GI side effects.
- Alcohol may increase hypoglycemia risk, particularly with concomitant insulin or secretagogues.
References
Related compounds
Important disclaimer
This page is an educational reference, not medical advice, a diagnosis, or a treatment recommendation, and not a substitute for your prescriber or pharmacist. Approval and regulatory status varies by compound and can change. Always confirm against current prescribing information and consult a qualified healthcare professional before making any decision about a medication.