Compound monograph
Tirzepatide
Also known as: Mounjaro, Zepbound, LY3298176
§1 Definition
Tirzepatide is a dual GIP/GLP-1 receptor agonist, an injectable peptide that activates both the glucose-dependent insulinotropic polypeptide and GLP-1 receptors to improve insulin secretion and promote weight loss. It is FDA-approved as Mounjaro for type 2 diabetes, and as Zepbound for chronic weight management and moderate-to-severe obstructive sleep apnea in adults with obesity.
Educational purposes only, not medical advice. Dosing figures below are documented ranges from cited literature, not a recommendation for any individual. Consult a qualified provider before administering anything.
§2 Evidence tier and regulatory status
Evidence tier
1 — FDA-approved
Approved by the FDA for at least one indication, backed by multiple randomized controlled trials.
FDA-approved. Mounjaro approved May 13, 2022 for glycemic control in type 2 diabetes. Zepbound approved November 8, 2023 for chronic weight management (BMI ≥30, or ≥27 with a weight-related comorbidity); the label was later expanded to include moderate-to-severe obstructive sleep apnea in adults with obesity.
§3 Documented dosing
| Context | Range | Frequency | Source |
|---|---|---|---|
| Type 2 diabetes glycemic control (Mounjaro) | 2.5–15 mg | once weekly, titrated in 2.5mg increments every 4+ weeks | [1], [2] |
| Chronic weight management, adults (Zepbound) | 2.5–15 mg | once weekly, titrated in 2.5mg increments every 4+ weeks; maintenance 5/10/15mg | [3], [4] |
| Moderate-to-severe obstructive sleep apnea with obesity (Zepbound) | 10–15 mg | once weekly maintenance, same titration start | [3], [4] |
§4 Reconstitution math
FDA-approved tirzepatide (Mounjaro, Zepbound) is supplied as a ready-to-use liquid solution in single-dose pens or vials — not a lyophilized powder requiring reconstitution. Compounded or research-grade tirzepatide sold as a lyophilized vial is not FDA-regulated, and no published primary-source reconstitution protocol exists for it; the vial sizes above reflect what is commonly sold by compounding sources, not an FDA-documented figure.
| Vial | Water | Concentration | Draw volume | Units (U-100) |
|---|---|---|---|---|
| 5 mg | 2.0 mL | 2500 mcg/mL | 1 mL | 100.0 |
| 10 mg | 2.0 mL | 5000 mcg/mL | 0.5 mL | 50.0 |
| 15 mg | 2.0 mL | 7500 mcg/mL | 0.333 mL | 33.3 |
This input can't be calculated:
- Draw volume exceeds the barrel capacity of the selected syringe.
§5 What the research shows
| Trial | Phase | n | Duration | Endpoint | Result | Source |
|---|---|---|---|---|---|---|
| SURMOUNT-1 | Phase 3 | 2539 | 72 weeks | Percent body weight change, adults with obesity/overweight without diabetes | Mean weight loss of 16.0% (5mg), 21.4% (10mg), and 22.5% (15mg) vs 2.4% with placebo. | [5] |
| SURPASS-2 | Phase 3, open-label | 1879 | 40 weeks | A1C and body weight change vs semaglutide 1mg, adults with type 2 diabetes on metformin | All three tirzepatide doses (5/10/15mg) achieved greater A1C and weight reduction than semaglutide 1mg; the 15mg arm's weight loss was roughly double the semaglutide 1mg arm's. | [6] |
§6 Safety and reported adverse effects
| Effect | Incidence | Source |
|---|---|---|
| Nausea (Mounjaro, 5/10/15mg) | 12% / 15% / 18% vs 4% placebo | [2] |
| Nausea (Zepbound, 5/10/15mg) | 25% / 29% / 28% vs 8% placebo | [4] |
| Diarrhea (Zepbound) | 19% / 21% / 23% vs 8% placebo | [4] |
| Vomiting (Zepbound) | 8% / 11% / 13% vs 2% placebo | [4] |
| Constipation (Zepbound) | 17% / 14% / 11% vs 5% placebo | [4] |
| Decreased appetite (Mounjaro) | 5% / 10% / 11% vs 1% placebo | [2] |
| Thyroid C-cell tumors | — | [1], [3] |
Thyroid C-cell tumor risk is a class-wide boxed warning based on rodent studies; human relevance is unknown and no human incidence rate has been published.
Contraindications
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Known hypersensitivity to tirzepatide or any excipient
Known interactions
- Increased hypoglycemia risk when combined with insulin or insulin secretagogues (class effect).
- Delayed gastric emptying can reduce absorption of oral hormonal contraceptives — a peer-reviewed pharmacy-journal source recommends switching to a non-oral contraceptive method, or adding a barrier method for 4 weeks after initiation and after each dose escalation.
§7 Storage and handling
- Lyophilized
- The FDA-approved product is not lyophilized (see reconstitution notes above).
- Reconstituted
- Reported as refrigerated at 2-8°C (36-46°F) until first use, with room-temperature storage up to 30°C (86°F) permitted for a limited period before first use only. This research pass could not independently confirm the exact FDA label wording for in-use duration, the same limitation noted on this site's semaglutide monograph — consult the product's patient information insert for the authoritative figure.
§8 Sourcing considerations
- Confirm the product is the FDA-approved pen or vial, not an unregulated compounded or "research use only" powder claiming to be tirzepatide.
- For any compounded version, ask for a Certificate of Analysis from an independent, named third-party lab, not the seller's own in-house testing.
- Confirm cold-chain shipping and handling were maintained, given the product's refrigeration requirements.
- Understand that compounded tirzepatide is not FDA-approved and its purity and potency are not FDA-verified.
§9 FAQ
What is tirzepatide used for?
Glycemic control in type 2 diabetes (as Mounjaro), and chronic weight management plus moderate-to-severe obstructive sleep apnea in adults with obesity (as Zepbound).
Is Mounjaro the same as Zepbound?
Same active ingredient and molecule, but different FDA-approved indications: Mounjaro for type 2 diabetes, Zepbound for chronic weight management and obstructive sleep apnea.
What is the tirzepatide starting dose?
2.5mg once weekly, titrated upward in 2.5mg increments every 4 or more weeks, for both Mounjaro and Zepbound.
Does tirzepatide need to be refrigerated?
Yes, before first use. See the storage section above for the caveat on post-first-use duration, which this page could not fully verify against the FDA label in this research pass.
What are the most common tirzepatide side effects?
Gastrointestinal effects — nausea, diarrhea, vomiting, and constipation — are the most commonly reported, and rates increase with dose. See the adverse effects table above for trial-reported incidence rates.
Is tirzepatide more effective than semaglutide?
In the head-to-head SURPASS-2 trial, all three studied tirzepatide doses achieved greater A1C reduction and weight loss than semaglutide 1mg in people with type 2 diabetes — see the trials table above.
Can tirzepatide cause thyroid cancer?
Unknown in humans. It carries the same class-wide boxed warning as other GLP-1/GIP therapies, based on thyroid C-cell tumors observed in rodent studies; human relevance has not been established.
Does tirzepatide affect birth control pills?
It can, by delaying gastric emptying and potentially reducing oral contraceptive absorption. A peer-reviewed source recommends a non-oral or additional barrier contraceptive method for 4 weeks after starting or increasing the dose.
§10 Sources
- [1] Mounjaro (tirzepatide) injection — Highlights of Prescribing Information. U.S. Food and Drug Administration, 2022. FDA. https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/215866s000lbl.pdf
- [2] MOUNJARO- tirzepatide injection, solution. DailyMed, National Library of Medicine (NIH), 2024. FDA. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0
- [3] ZEPBOUND (tirzepatide) injection — Highlights of Prescribing Information. U.S. Food and Drug Administration, 2024. FDA. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/217806s003lbl.pdf
- [4] ZEPBOUND- tirzepatide injection, solution. DailyMed, National Library of Medicine (NIH), 2024. FDA. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b
- [5] Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine, 2022. Peer-reviewed. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
- [6] Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2). New England Journal of Medicine, 2021. Peer-reviewed. https://www.nejm.org/doi/full/10.1056/NEJMoa2107519
- [7] The Impact of Tirzepatide and Glucagon-Like Peptide 1 Receptor Agonists on Oral Hormonal Contraception. Journal of the American Pharmacists Association, 2023. Peer-reviewed. https://www.japha.org/article/S1544-3191(23)00370-9/fulltext