Independent. Not affiliated with Eli Lilly or Novo Nordisk.Not medical advice. Your prescriber decides your treatment.
GLP-1 Field GuidePractical help, sourced from the label

How to inject Mounjaro, step by step

Mounjaro comes as a single-dose pen, a multi-dose KwikPen and vials, and each works differently. Find yours below. Every step is summarized from Lilly's Instructions for Use.

Compiled by the GLP-1 Field Guide editorUpdated 6 min readSourced from official labels. Not yet clinically reviewed.
Key points
  • Inject once a week, any time of day, with or without meals.
  • Use your stomach or thigh. The back of the upper arm is for when someone else injects.
  • Single-dose pen: base flat on skin, unlock, press and hold up to 10 seconds until the second click.
  • KwikPen: new needle, prime, dial to the icon, push and count to 5.
  • Vial: keep the needle in your skin for at least 5 seconds.

Where to inject

You or another person can inject Mounjaro into your stomach (abdomen) or thigh. Another person should give the injection if you use the back of your upper arm.[1] Change (rotate) your injection site each week. You may use the same area of your body, but choose a different site within that area.[1] The KwikPen instructions add: stay at least 2 inches from the belly button.[2]

The free injection site logbook has Mounjaro built in and shows which spot has rested longest.

Front
Back
Stomach (abdomen) and front of thighsBack of upper arms: only if someone else injectsKeep 2 inches from the belly button
Where to inject Mounjaro, from Lilly's instructions. Rotate to a new spot each week.

Single-dose pen

The single-dose pen has a built-in needle. There is nothing to attach or prime.[1]

  1. Check the pen is locked, then remove the gray base cap

    Leave the cap on until you are ready. Pull it straight off and throw it away in your household trash. Do not put it back on, as this could damage the needle.

  2. Place and unlock

    Place the clear base flat against your skin at the injection site, then unlock by turning the lock ring.

  3. Press and hold

    Press and hold the purple injection button for up to 10 seconds. First click: the injection has started. Second click: it is complete. Some people hear a soft click just before the second loud click.

  4. Check

    The injection is complete when the gray plunger is visible.

Summarized from the Mounjaro single-dose pen Instructions for Use (April 2026).[1]

Mounjaro KwikPen

The US Mounjaro label includes a single-patient-use KwikPen.[4] Each pen contains 4 fixed doses, one dose taken weekly, and needs a new pen needle for each injection.[2]

  1. Attach a new needle

    Push the capped pen needle straight onto the pen and twist until it is tight.

  2. Prime before every weekly injection

    Slowly turn the dose knob until you hear 2 clicks and the extended line is shown. Push the dose knob in until it stops and slowly count to 5. The pen is primed if a drop of medicine comes out.

  3. Dial your dose

    Turn the dose knob all the way until it stops and the icon is in the dose window. Do not count clicks.

  4. Inject

    Insert the needle, push the dose knob in until it stops, then slowly count to 5 while holding it.

Summarized from the Mounjaro KwikPen Instructions for Use (January 2026).[2]

Throw the KwikPen away 30 days after first use, or after 4 weekly doses.[2] The label says the KwikPen is not recommended for self-injection by children or by people who are visually impaired, and that a KwikPen must never be shared between patients.[4]

Vials

Mounjaro also comes in single-dose and multi-dose vials, used with a syringe and needle. Keep the needle in your skin for at least 5 seconds after injecting.[3] Follow the Instructions for Use for your vial type exactly, and use the syringe your prescriber or pharmacist specifies.

Timing and missed doses

Take Mounjaro once weekly, any time of day, with or without meals.[4] If you miss a dose, take it as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your regular day. You can change your injection day as long as there are at least 3 days (72 hours) between doses.[4]

Mounjaro is approved, with diet and exercise, to improve blood sugar in adults and children 10 years and older with type 2 diabetes, and to reduce the risk of major cardiovascular events in adults with type 2 diabetes who are at high risk.[4]

Common questions

How long do you hold the Mounjaro pen?

Press and hold the purple injection button for up to 10 seconds. The first click means the injection has started; the second click means it is complete. The gray plunger becomes visible when it is done.

Where can I inject Mounjaro?

You or another person can inject into your stomach (abdomen) or thigh. Another person should give the injection if you use the back of the upper arm. Rotate the injection site each week.

Is there a Mounjaro KwikPen in the US?

Yes, the US Mounjaro label includes a single-patient-use KwikPen holding 4 weekly doses, with its own Instructions for Use. Ask your pharmacy which Mounjaro device they supply.

I heard a third click. Is that normal?

Lilly says some people may hear a soft click right before the second loud click. That is normal operation of the pen.

What is Mounjaro approved for?

Mounjaro is approved, with diet and exercise, to improve blood sugar in adults and children 10 and older with type 2 diabetes, and to reduce the risk of major cardiovascular events in adults with type 2 diabetes at high risk.

Not medical adviceThis guide explains what the official instructions say. Your prescriber and pharmacist know your situation, so ask them if anything here does not match what you were told.

Sources

  1. Eli Lilly and Company. Mounjaro single-dose pen Instructions for Use. Revised April 2026. Last checked 2026-10-01.
  2. Eli Lilly and Company. Mounjaro KwikPen Instructions for Use. Revised January 2026. Last checked 2026-10-01.
  3. Eli Lilly and Company. Mounjaro single-dose vial Instructions for Use. Revised April 2026. Last checked 2026-10-01.
  4. Eli Lilly and Company. Mounjaro (tirzepatide) Prescribing Information. Revised 08/2026. Last checked 2026-10-01.
Injection site logbookPick Mounjaro and track your rotation.How to store MounjaroThe 21 and 30-day rules by device.How to inject ZepboundSame medicine, similar devices.