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Zepbound ® (tirzepatide) injection
2.5 mg/ 5 mg/ 7.5 mg/ 10 mg/ 12.5 mg/ 15 mg
This information is provided in response to your request. Resources may contain information about doses, uses, formulations and populations different from product labeling. See Prescribing Information above, if applicable.
Are the different Zepbound® (tirzepatide) presentations bioequivalent?
Based on bioequivalence studies, tirzepatide is expected to demonstrate comparable efficacy and safety across the different formulations.
See important safety information, including boxed warning, in the attached prescribing information.
Content Overview
- What Zepbound (Tirzepatide) Presentations Are Approved?
- Which Tirzepatide Presentation Was Used In Clinical Studies?
- Does Benzyl Alcohol Increase the Risk of Metabolic Acidosis?
- Can Patients Switch Between Tirzepatide Presentations?
- Enclosed Prescribing Information
- References
What Zepbound (Tirzepatide) Presentations Are Approved?
Zepbound (tirzepatide) is approved by the Food and Drug Administration (FDA) in a
- single-dose pen
- multiple-dose pen
- single-dose vial, and
- multiple-dose vial.1
The pens and the vials have the identical active ingredient, tirzepatide, and are designed to deliver the same doses.1
Regardless of presentation, tirzepatide is administered subcutaneously once weekly, and the dosing regimen and administration sites (abdomen, thigh or back of upper arm) remain the same.1
The FDA has approved the Zepbound KwikPen and multiple dose vial.1
Which Tirzepatide Presentation Was Used In Clinical Studies?
Phase 3 clinical trials of tirzepatide for chronic weight management and obstructive sleep apnea were conducted using the tirzepatide single-dose pen.2-7
The tirzepatide multidose presentations and the tirzepatide single-dose presentations have the identical active ingredient, tirzepatide, and are designed to deliver the same doses as the single-dose pen that that was tested in the SURMOUNT clinical trial program in adults with obesity or overweight or moderate-to-severe obstructive sleep apnea and obesity.1-6
Based on the results of bioequivalence studies, the efficacy and safety of tirzepatide administered between the autoinjector and other presentations can be expected to be comparable.
This includes the same excipients, excipient concentrations, and drug substance concentration.7
The single-dose vial and single-dose pen
- contain 1 fixed dose
- have a dosing volume of 0.5 mL per dose
- are for single use only, and
- do not contain preservatives.1
Differences between the single-dose presentations and multi-dose presentations include
- the dosing volume and
- the addition of the preservatives, phenol and benzyl alcohol, and the tonicity agent, glycerin as summarized in Table 1.7
Table 1. Tirzepatide Formulation Ingredients7
|
Tirzepatide Single-dose Pen or Vial (Nonpreserved Formulation) |
Tirzepatide Multi-dose Pen or Vial |
|---|---|---|
Ingredienta |
Quantity (per 0.5 mL) |
Quantity (per 0.6 mL) |
Tirzepatide |
2.5 mg/5 mg/7.5 mg/10 mg/ |
2.5 mg/5 mg/7.5 mg/10 mg/ |
Dibasic sodium phosphate heptahydrate |
0.7 mg |
0.8 mg |
Sodium chloride |
4.1 mg |
1.05 mg |
Hydrochloric acid solution |
as needed |
as needed |
Sodium hydroxide solution |
as needed |
as needed |
Water for injection |
as needed to 0.5 mL |
as needed to 0.6 mL |
Phenol |
NA |
1.08 mg |
Benzyl alcohol |
NA |
5.4 mg |
Glycerin |
NA |
4.8 mg |
Abbreviation: NA = not applicable.
a Only the KwikPen contains preservatives (benzyl alcohol, phenol) and glycerin for tonicity.
Does Benzyl Alcohol Increase the Risk of Metabolic Acidosis?
Eli Lilly and Company has no clinical trial data on the risk of metabolic acidosis associated with benzyl alcohol in tirzepatide multi-dose presentations.
Patients should ask their doctor, nurse or pharmacist for advice if they are pregnant or breast-feeding, or if they have kidney or liver problems. This is because large amounts of benzyl alcohol can build-up in their body and may cause metabolic acidosis.7
Can Patients Switch Between Tirzepatide Presentations?
There are no data available regarding transitioning between the tirzepatide presentations, as these treatment scenarios have not been studied.
Eli Lilly and Company has created several different presentations to deliver tirzepatide, but cannot make a specific recommendation on which presentation of tirzepatide is best for each patient. The healthcare practitioner may use the information provided, the patient’s prior medical history and concomitant medications, and other individual factors in developing a treatment plan. The healthcare practitioner should consider potential risks and benefits of treatment options and monitor appropriately.
Tirzepatide presentations have the identical active ingredient and are designed to deliver the same doses. Regardless of presentation, tirzepatide is administered subcutaneously once weekly, and the dosing regimen and administration sites remain the same.7
Please follow the Zepbound Prescribing Information for instructions on proper administration of tirzepatide.1
Patients should always consult their health care provider to understand the risks and benefits of tirzepatide and to determine whether they may benefit from tirzepatide, including the dose and delivery mechanism best suited for them.7
Prior to initiation of any formulation of tirzepatide, healthcare providers should train patients and caregivers on proper injection technique. Refer to your local label for instructions on proper storage, handling, and administration of tirzepatide via the KwikPen or the single-dose vial to ensure accurate and effective dosing of tirzepatide.
Enclosed Prescribing Information
ZEPBOUND® (tirzepatide) injection, for subcutaneous use, Lilly
References
The published references below are available by contacting 1-800-LillyRx (1-800-545-5979).
- Zepbound [package insert]. Indianapolis, IN: Eli Lilly and Company; 2026.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al; SURMOUNT-1 Investigators. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387(3):205-216. https://doi.org/10.1056/NEJMoa2206038
- Garvey WT, Frias JP, Jastreboff AM, et al; SURMOUNT-2 investigators. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet. 2023;402(10402):613-626. https://doi.org/10.1016/S0140-6736(23)01200-X
- Wadden TA, Chao AM, Machineni S, et al. Tirzepatide after intensive lifestyle intervention in adults with overweight or obesity: the SURMOUNT-3 phase 3 trial. Nat Med. 2023;29(11):2909-2918. https://doi.org/10.1038/s41591-023-02597-w
- Aronne LJ, Sattar N, Horn DB, et al; SURMOUNT-4 Investigators. Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity: the SURMOUNT-4 randomized clinical trial. JAMA. 2024;331(1):38-48. https://doi.org/10.1001/jama.2023.24945
- Malhotra A, Grunstein RR, Fietze I, et al; SURMOUNT-OSA Investigators. Tirzepatide for the treatment of obstructive sleep apnea and obesity. N Engl J Med. 2024;391(13):1193-1205. https://doi.org/10.1056/NEJMoa2404881
- Data on file, Eli Lilly and Company and/or one of its subsidiaries.
Date of Last Review: July 29, 2026