How to Inject Zepbound and Mounjaro Pens

How do you inject the Zepbound or Mounjaro pen step by step?

To inject Zepbound, press the single-dose pen flat against clean skin on the abdomen or thigh, unlock it, press the purple button and keep holding until you hear the second click. Lilly's Mounjaro Instructions for Use for the single-dose pen use the same click wording. The Zepbound Instructions for Use say to hold for up to 10 seconds, then check that the gray plunger is visible.

In short

• The Zepbound Instructions for Use say to press and hold the purple button for up to 10 seconds, with the first click meaning the injection has started and the second meaning it has finished.
• The same Instructions for Use say the dose is complete when the gray plunger is visible, that air bubbles are normal, and that you should call 1-800-Lilly-Rx (1-800-545-5979) if the plunger is not visible.
• Lilly's single-dose pen is refrigerated at 36°F to 46°F (2°C to 8°C) and may stay at up to 86°F (30°C) for a total of up to 21 days, while the Mounjaro KwikPen needs a needle and priming.

The steps below follow the order of the Instructions for Use in the US Zepbound and Mounjaro labels for the single-dose pen. Other markets and presentations have their own leaflets, so keep the one from your box open while you inject.

1. Check which pen you have. The single-dose pen has no needle to attach. If your pen needs a needle attached and a dose knob turned, it is the KwikPen, covered further down.
2. Choose a site and clean the skin. The abdomen or thigh are the sites for injecting yourself. Pick a spot you did not use last week.
3. Remove the base cap. The Instructions for Use list this before the pen is placed on the skin.
4. Place the pen flat against the skin and unlock it. Keep it flat on the skin you cleaned.
5. Press and hold the purple injection button. The first click means the injection has started. Keep holding until the second click means it has finished.
6. Check the gray plunger. If it is visible, the dose is complete.
7. Write down the site. Next week you will want to pick a different spot.

The steps list no measuring, mixing or priming. If anything looks different from your Instructions for Use, follow the leaflet in your box and ask your prescriber or pharmacist.

What questions does this guide answer?

This guide answers the following questions about the tirzepatide pen, in reading order, using the Instructions for Use and the prescribing information.

• How long to hold the pen, and what the two clicks mean
• What the label says to do if the gray plunger is not visible
• Whether a bubble or a drop of liquid matters
• Which injection sites exist and how to rotate them
• How the Mounjaro KwikPen differs from the single-dose pen
• How to store the pen, and for how long at room temperature
• A side-by-side table, the mistakes that cost the most, warning signs, and a short FAQ

Medicine choice, dose and timing are decisions for you and your prescriber. This guide describes only what the labels say about the device.

How long do you hold the Zepbound pen, and what do the two clicks mean?

The Zepbound Instructions for Use tell you to press and hold the purple injection button for up to 10 seconds. You can read the label text in the Zepbound prescribing information on DailyMed.

The first click means the injection has started. The second click means the injection has been completed. Lilly's own how to use Mounjaro page gives the same click wording for the Mounjaro pen.

The first click means the injection has started, not that it has finished, so keep holding until the second click. Then confirm with the plunger.

If you hear only one click, check the plunger and read the next section. The hold time and the click meanings are the same whether the pen is labelled Zepbound or Mounjaro in the Instructions for Use.

What if the gray plunger isn't visible after the injection?

The Instructions for Use state that the injection is complete when the gray plunger is visible. If the gray plunger is not visible, the label directs you to call 1-800-Lilly-Rx (1-800-545-5979). That is the number printed for this exact situation.

Your prescriber decides about any further dose. The call to Lilly is the label's step, and your prescriber or pharmacist can help with what follows.

The label ties completion to the gray plunger, so check it after every shot, whether or not the clicks seemed normal.

What if there's a bubble or a drop of liquid after the shot?

The Instructions for Use say air bubbles are normal. The label gives no instruction to remove a bubble.

The label's completion check is the two clicks and the gray plunger.

• If you heard the second click and the plunger is visible, the Instructions for Use treat the dose as complete.
• If the plunger is not visible, call 1-800-Lilly-Rx (1-800-545-5979), as the label says.
• If you see liquid or think the pen leaked and you are unsure the dose was delivered, call 1-800-Lilly-Rx or your pharmacist. Your prescriber decides about anything further.

Pressing the pen flat and holding it until the second click is what the label describes. Follow those steps each time.

Where are the Zepbound injection sites, and how often do you rotate them?

The Zepbound Instructions for Use name the abdomen or thigh for injecting yourself, and the back of the upper arm if another person gives the shot. Rotate the site each week. You may use the same body area, but choose a different spot within it.

That wording is from the single-dose pen section of the Zepbound prescribing information. Lilly's Mounjaro page repeats the weekly rotation guidance.

A written record makes rotation easy. Note the area and side after each shot, or log it in an app. Then next week's choice is a glance at the last entry.

For the KwikPen, the Lilly Germany guidance says at least 5 cm from the navel for the abdomen.

The label's rule is a different spot each week.

How does the Mounjaro KwikPen differ from the single-dose pen?

Lilly's KwikPen documents describe a different device from the single-dose pen: you attach a needle and prime the pen. The active ingredient is tirzepatide in both. The single-dose steps in this guide come from the US Zepbound and Mounjaro labels, and other markets and presentations have their own leaflets.

Mounjaro is authorized in the EU, as the EMA Mounjaro page shows. Following a single-dose guide with a KwikPen means missing steps that matter.

KwikPen details from Lilly's own documents:

• Priming. Lilly's Spanish KwikPen Instructions for Use say to turn to the priming position (2 clicks), push the dose knob to the stop and hold while counting slowly to 5.
• Abdomen. Lilly Germany's KwikPen guidance says at least 5 cm from the navel.
• Discard. The KwikPen wording in the Lilly Instructions for Use text on DailyMed says to discard the pen 30 days after first use, even if medicine remains, or after 4 weekly doses, whichever comes first.

Use the leaflet in your own box. If it shows a dose knob and a needle you attach, follow the KwikPen leaflet and not the single-dose steps in this guide.

How should the Zepbound pen be stored, and for how long at room temperature?

The Instructions for Use say to keep the single-dose pen in the refrigerator at 36°F to 46°F (2°C to 8°C). It may be kept at up to 86°F (30°C) for a total of up to 21 days, then discarded. Both figures come from the Zepbound prescribing information on DailyMed.

The word "total" matters. The 21 days is the sum of all the time out of the fridge, not a fresh 21 days each time you take the pen out. A tally on your calendar is enough to keep track.

Here is an illustrative example. Illustrative figures: if a pen spends 8 days at room temperature on a trip and 5 days on another, the total is 8 + 5 = 13 days. That leaves 21 − 13 = 8 days of the allowance. These numbers are invented to show the sum, not taken from the label.

Your Instructions for Use list the other storage conditions.

If you use a KwikPen, the discard rule is different: 30 days after first use, or after 4 weekly doses, whichever comes first. Do not apply the single-dose pen's 21 days to it.

After the injection, you may wonder when the effect begins. How long Mounjaro takes to reach a steady effect is explained by the label's schedule, and how long a GLP-1 medicine's effect lasts between doses is set out in a week-by-week table. The GLP-1 half-life calculator estimates tirzepatide left in the body from the dose, number of shots and time of the last shot you enter. It never suggests a dose.

How do the two pen designs compare side by side?

The table below lines up the single-dose pen and the Mounjaro KwikPen on needle, priming, site and storage or discard. It does not cover hold time or completion signals for the KwikPen, so use its leaflet for those. The first column comes from the US Zepbound and Mounjaro Instructions for Use. The second comes from the Lilly KwikPen documents cited in the sources.

Read the table by the pen in your hand. Both devices deliver tirzepatide once a week, but they ask you to do different things. For hold time, clicks and the completion check on the single-dose pen, see the sections above.

The label also gives weekly rules that apply either way, quoted here from Lilly's patient page. Leave at least 3 days (72 hours) between doses if you change your dose day. A missed dose can be taken within 4 days (96 hours), and beyond that it is skipped and the regular day resumes. Never take two doses within 3 days of each other. Your prescriber decides what applies to you.

Which mistakes cost the most when you inject a pen?

The mistakes below are the ones the label wording points to, from letting go early to mixing up devices. None of them is a dosing instruction.

• Do not lift the pen at the first click. The first click means the injection has started, and the second means it has finished.
• Do not skip the plunger check. The label calls the dose complete only when the gray plunger is visible. If it is not, call 1-800-Lilly-Rx (1-800-545-5979).
• Do not follow a KwikPen guide with a single-dose pen, or the reverse. Priming a device that needs none, or skipping it on one that does, is the mix-up the comparison table is built to prevent.
• Do not lose track of room-temperature days. The 21-day allowance is a total for the single-dose pen, so tally the days you take the pen out of the fridge.

A fifth habit is worth adding, though it is not a label rule: record the site every week. A log turns rotation into a glance at the last entry.

When should you contact a doctor about an injection or side effect?

Contact your prescriber or pharmacist for any injection problem the leaflet does not cover, and seek emergency care for severe symptoms of the serious side effects named in the Zepbound Medication Guide. The guide is part of the Zepbound prescribing information on DailyMed.

The Medication Guide lists these serious side effects, with the signs to watch for:

• thyroid C-cell tumors, with a lump or swelling in the neck, hoarseness or trouble swallowing
• pancreatitis, with severe stomach pain, with or without vomiting
• gallbladder problems
• serious allergic reactions, such as swelling of the face, lips or tongue, or trouble breathing
• kidney problems and dehydration
• low blood sugar
• vision changes
• suicidal thoughts

Read the full wording in your own Medication Guide, because it describes each sign in more detail.

Common reactions are listed separately. The Zepbound label reports nausea in 25%, 29% and 28% of people on 5 mg, 10 mg and 15 mg over 72 weeks, against 8% on placebo. The Mounjaro label, in type 2 diabetes, reports nausea in 12%, 15% and 18% on the same three doses against 4% on placebo. The two figures come from different populations and indications, so they are not a ranking.

How can Dose & Lose help you log the shot?

Dose & Lose is a GLP-1 companion app for iPhone and Android that logs each dose with the medication, the dose, the date and time, the injection site, a pain level from 0 to 10 and notes. It is a tracking app. It does not prescribe, supply or give dosing advice.

With rotation turned on, the app remembers where the last injection went and suggests the next site on the other side. It suggests, and you choose. You can also set a reminder time and get a notification on dose days.

It also draws an estimate of how much medication is active from the doses you log. That is an estimate from a fixed model, not a lab value.

See the Dose & Lose app page. The app's interface is in English only. Logging doses, side effects, water, weight and food is free.

Frequently asked questions

What if I don't see the second click or the gray plunger?

Call 1-800-Lilly-Rx (1-800-545-5979). The Instructions for Use say the injection is complete when the gray plunger is visible, and they tell you to call if it is not. Your prescriber decides about any further dose, so tell them what happened.

Is the Zepbound pen the same as the Mounjaro pen?

In the US labels, the single-dose pen instructions use the same click wording, and both medicines contain tirzepatide. Other markets and presentations, such as the Mounjaro KwikPen, have their own leaflets with a needle and priming steps. Follow the Instructions for Use that came with your pen.

Do I need to pinch my skin before injecting?

The steps in this guide do not include pinching. You press the single-dose pen flat against clean skin, unlock it and press the button. If your Instructions for Use or your prescriber describes a different technique for your pen, follow that, because the leaflet in your box is the final authority.

Can someone else give me the injection in my arm?

Yes. The Zepbound Instructions for Use name the back of the upper arm as a site when another person gives the injection. When you inject yourself, the label names the abdomen or thigh. The helper follows the same steps: pen flat, unlock, hold until the second click, check the plunger.

Are air bubbles a problem?

No. The Instructions for Use say air bubbles are normal. Judge the dose by the two clicks and the visible gray plunger. If the plunger is not visible, call 1-800-Lilly-Rx (1-800-545-5979) as the label directs, and let your prescriber decide about anything further.

Where do these figures come from?

Every figure in this guide comes from the labels and Lilly pages below. Each link goes to the record itself.

• Zepbound prescribing information with Instructions for Use, DailyMed: hold time, clicks, plunger, bubbles, sites, rotation, storage, nausea rates and warning signs.
• Mounjaro prescribing information, DailyMed: the Mounjaro label, its single-dose pen instructions and its nausea rates.
• Lilly, how to use Mounjaro: the click wording, dose-day change rule and missed-dose window.
• Lilly Spain, Instrucciones de uso Mounjaro KwikPen: KwikPen priming steps.
• Lilly Germany, Mounjaro KwikPen guidance: the 5 cm distance from the navel.
• EMA, Mounjaro product page: Mounjaro's authorization in the EU.

Published by Petros IT Solutions SRL, byline Dose & Lose Editorial Team. This guide is educational and is not personal medical advice. To report an error, write to office@doseandlose.com.