Mounjaro (tirzepatide) single-dose pen administration as described in the current Eli Lilly prescribing information. Step-numbered procedure, supplies checklist, common mistakes. Educational only, not medical advice.
Key points
- 01Inspect the pen. Confirm dose match on the label. The Lilly Instructions for Use specifies that the Mounjaro solution be clear and colourless to slightly yellow. Cloudy, discoloured, or particle-containing solution is discarded.
- 02Pull off the gray base cap. Pull the gray cap straight off the bottom of the pen. The cap is discarded in regular trash, not the sharps container.
- 03Clean the injection site. Swab with the alcohol prep pad and let the alcohol air-dry for at least 10–15 seconds before injecting.
- 04Place the pen against the skin. Hold the pen flat against the skin with the clear base flush against the chosen site at a 90-degree angle. The hidden needle does not extend until the dose button is pressed.
- 05Press the purple injection button. Press the purple button at the top of the pen. The first click signals the injection has started. Continue holding the pen firmly against the skin.
- 06Wait for the second click. Eli Lilly's Instructions for Use specifies holding the pen in place until a second click is heard, which indicates the dose has been delivered. Lilly recommends counting slowly to 10 after the first click as a fallback timer.
- 07Lift the pen and confirm. Pull the pen straight up off the skin. Confirm through the inspection window that the gray plunger has descended fully, this is the visual confirmation that the dose was delivered.
- 08Dispose of the pen. Drop the entire pen into an FDA-cleared sharps container. The Mounjaro pen is single-use. Do not recap or handle the needle.
Pre-injection checklist
- ✓Wash hands for at least 20 seconds, or use an alcohol-based hand rub.
- ✓Verify the dose on the carton label matches the prescription.
- ✓Inspect the solution through the inspection window, Eli Lilly's Instructions for Use describes the Mounjaro solution as clear and colourless to slightly yellow. A cloudy or discoloured solution is grounds to discard.
- ✓Allow 30 minutes at room temperature if the pen was just removed from the fridge.
- ✓Choose an injection site (abdomen at least 2 inches from the navel, front of either thigh, or back of either upper arm if a caregiver is administering).
After the injection
- Press a cotton ball or gauze square to the site for 10–15 seconds if any bleeding.
- Log date, dose, and injection site.
- Return the carton to refrigerated storage 36–46°F (2–8°C), or hold at room temperature ≤ 86°F (30°C) for up to 21 days.
Common mistakes
- Severe abdominal pain that does not resolve, pancreatitis warning in the Mounjaro prescribing information.
- Swelling of face, throat, or tongue, or difficulty breathing, serious allergic reaction.
- Severe upper-right abdominal pain, fever, or yellowing of skin or eyes, gallbladder disease.
- Severe vomiting or diarrhoea preventing fluid intake, acute kidney injury risk.
- Vision changes in adults with type-2 diabetes, diabetic retinopathy concern.
Frequently asked questions
Is Mounjaro the same procedure as Zepbound?+
Yes. The two products use the same single-dose hidden-needle pen, the same molecule (tirzepatide), and the same step-numbered procedure. The differences are the FDA-approved indication (Mounjaro for type-2 diabetes; Zepbound for chronic weight management) and the dose-titration cadence the prescriber selects. The pen mechanics, the inspection step, the press-and-wait-for-second-click sequence, and the disposal procedure are identical across the two products.
Can I use a Mounjaro pen prescribed in 2024 if it has been refrigerated continuously?+
Check the expiration date printed on the carton and the pen. Mounjaro's prescribing information specifies that the device be used by the printed expiration date when stored continuously refrigerated. An expired pen is discarded regardless of how it has been stored. The 21-day room-temperature window does not extend the printed expiration.
What if I miss a Mounjaro dose?+
Eli Lilly's prescribing information directs that a missed dose be taken within 4 days (96 hours). After 4 days, the missed dose is skipped and the next dose taken on the regular schedule. Doubling up to make up a missed dose is not supported. For a full schedule reset, contact the prescriber's office.
Why does the Mounjaro pen sting more than my insulin pen?+
Two reasons. Mounjaro is injected weekly at a higher delivered volume than most insulin pens, and the solution may be slightly cooler if the 30-minute room-temperature window was skipped. Allowing the pen to warm and ensuring the alcohol prep pad has dried completely before the needle goes in addresses both. If injection-site pain persists or worsens across multiple doses, raise it with the prescriber.
Where do I rotate among?+
Eli Lilly's Instructions for Use specifies abdomen (avoiding 2 inches around the navel), front of either thigh, and back of either upper arm if a caregiver administers. Weekly rotation across abdomen quadrants gives each site three weeks of rest. See our rotating-injection-sites post for the labeled site-rotation diagram.
Sources
- Eli Lilly. Mounjaro (tirzepatide) Instructions for Use, single-dose pen.
- Eli Lilly. Mounjaro (tirzepatide) Prescribing Information.
- Frias JP et al. 2021. Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes (SURPASS-2). New England Journal of Medicine 385(6):503–515.
- FDA. Drugs@FDA, Mounjaro labeling.
- FDA. Best Way to Get Rid of Used Needles and Other Sharps.
- CDC. Safe Injection Practices.
