Brand-name pens: what the makers' own instructions say
Quick answer. Each brand-name pen comes with a written instruction sheet from its maker, and the steps are not the same for every pen. The Lilly pens (Zepbound, Mounjaro) have a lock ring and a purple button. The Wegovy pen has no lock and shows a yellow bar. This page summarizes those sheets in plain English. It gives no doses, and the sheet in your box and your clinician come first.
What this page is, and what it is not
This page retells what three makers say in their own written instructions for use. It is a reading aid. It is not training, and it does not replace the sheet in your box, the label, or a clinician or pharmacist showing you how.
It covers only single-dose pens made by the drug company. It does not cover vials, syringes, compounded products or pens from other sources, because there are no maker instructions for those. The injection instructions checklist explains how to judge instructions for those products instead.
It also gives no doses, no schedules and no advice on missed doses. Those come from the label and your prescriber. Instructions are revised from time to time, so if this page and the sheet in your hand disagree, follow the sheet.
Which pens are covered
The two Lilly pens use the same steps, so they share a column below. Other devices from these makers, such as pens you set to a dose or attach a needle to, have their own sheets and are not covered here.
Before you inject
| Step | Zepbound and Mounjaro pens (Lilly) | Wegovy pen (Novo Nordisk) |
|---|---|---|
| Take the pen out and check it | Take it out of the refrigerator and keep the gray base cap on. Check that the label shows the right medicine, the right dose and an expiry date that has not passed. | Check that the pen does not look used or broken and that the expiry date has not passed. |
| Look at the medicine | It should be colorless to slightly yellow. Do not use it if it is frozen, cloudy or has particles. | It should be clear and colorless. Air bubbles are normal. Do not use it otherwise. |
| Wash your hands | Yes, before you start. | Yes, before you start. |
| Supplies | The sheet points you to a sharps container for the used pen. | The maker lists the pen, an alcohol swab or soap and water, a gauze pad or cotton ball, and a sharps container. |
| Cleaning the skin | The Lilly sheet we read does not describe cleaning the skin. | Clean the site, let it dry and do not touch it again. |
Where the makers say to inject
| Question | Zepbound and Mounjaro pens (Lilly) | Wegovy pen (Novo Nordisk) |
|---|---|---|
| Which areas | Stomach area or thigh. Back of the upper arm only if another person gives the injection. | Front of the thigh, stomach (about 2 inches from the belly button) or upper arm. You must be able to see the pen window. |
| Rotating | Use a different spot each week. The same general area is fine. | Rotate each week and do not use the exact same spot. |
| Skin to avoid | Not described in the sheet we read. | Skin that is tender, bruised, red or hard, and scars or stretch marks. |
The injection, side by side
This is where the pens differ most, and it is why one pen's habits should not be carried over to another. Read the column for your pen only.
| Moment | Zepbound and Mounjaro pens (Lilly) | Wegovy pen (Novo Nordisk) |
|---|---|---|
| Cap | With the lock still on, pull the gray base cap straight off and throw it away. Do not put it back on, because that could damage the needle. Do not touch the needle. | Pull the cap straight off. The needle is hidden. Do not push on the needle cover. |
| Positioning | Put the clear base flat against your skin first. Only then turn the lock ring to release the lock. | Push the pen firmly against your skin and keep pressing. |
| Starting | Press and hold the purple button. | Pressing firmly starts it. The yellow bar moves when the injection has started. If it does not move, press harder. |
| What you hear and see | A first click means the injection has started. A second click means it is complete. The gray plunger shows when it is done. | Two clicks. The maker says not to stop at two clicks. Keep pressing until the yellow bar stops moving. |
| How long | Hold for up to 10 seconds. | Roughly 5 to 10 seconds, per the maker's pages. |
| Taking it off the skin | Do not lift the pen until you hear the second click. | Lift it slowly once the yellow bar has stopped. |
| Afterward | Do not rub the site. If a drop of liquid or blood shows, press a cotton ball or gauze on it. | If blood shows, press lightly with gauze or a cotton ball. |
When the sheets say a step went wrong
- Lilly: if you took the cap off, released the lock or pressed the button in the wrong order, throw that pen away and use a new one. If the gray plunger is not visible afterward, contact Lilly using the number on the sheet and store the pen safely until you hear back.
- Lilly: do not use a pen that has been frozen or dropped on a hard surface. The pen has glass parts.
- Novo Nordisk: if the pen has a problem, keep the pen and its packaging and contact the maker's customer care number on the sheet, instead of throwing it away.
- Lilly states that people with vision problems should not use the pen without help from someone trained. For any pen, if you are unsure, ask your clinician or pharmacist to watch you do it first.
- If a dose seems incomplete, the Atlas found no instruction in these sheets on what to do about the medicine itself. That is a question for your prescriber.
Storage, as the makers describe it
| Point | Zepbound and Mounjaro pens (Lilly) | Wegovy pen (Novo Nordisk) |
|---|---|---|
| In the refrigerator | 36°F to 46°F (2°C to 8°C). | In the refrigerator in the original box, away from light. |
| Out of the refrigerator | Up to 86°F (30°C) for a total of 21 days, then throw it away. | Up to 28 days at 46°F to 86°F in the carton with the cap on. |
| Freezing | Do not freeze. Throw away a pen that has frozen. | Do not freeze. |
| Light and carton | Keep it in the original carton to protect it from light. | Keep it in the carton to protect it from light, with the cap on until you inject. |
| Children and sharing | Keep the pen and all medicines out of children's reach. | The Wegovy pages say not to share the pen with others. |
Throwing the pen away
Both makers say the used pen goes into an FDA-cleared sharps container right away. It does not go in the household trash. If you do not have a sharps container, both describe a sturdy household container with a tight lid that stands upright, does not leak and is labeled as holding hazardous waste.
Do not recycle a full sharps container, and follow your local rules for getting rid of it when it is nearly full. Novo Nordisk's page points to safeneedledisposal.org for local drop-off sites. Rules differ by state and town, so your pharmacy or local health department can tell you what applies to you.
What these sheets share, and where to go next
To see the originals, use the links in the sources below. For doses and schedules, see the label and your prescriber. The week-by-week side effects page and the compounded versus brand-name page cover what comes next.
- Every one tells you to check the pen and the medicine before you use it.
- Every one has you rotate the injection spot week to week.
- Every one treats the used pen as sharps waste.
- None of them replaces training. Ask your clinic or pharmacy to walk you through your first dose.
Quick answers
- Where do I find the official instructions for my pen?
- In the box with the pen, and on the maker's website and the FDA-posted label. The sources below link to the Lilly instruction sheets and to Novo Nordisk's Wegovy pages.
- Do the Zepbound, Mounjaro and Wegovy pens work the same way?
- No. The Lilly pens have a lock ring and a purple button. The Wegovy pen has no lock and shows a yellow bar. Follow the sheet for the pen you have.
- How many clicks should I hear?
- The Lilly sheet describes a click at the start and a second click when the injection is complete. The Wegovy sheet says two clicks and to keep pressing until the yellow bar stops. Do not use one pen's rule for the other.
- Where on the body do the makers say to inject?
- Lilly names the stomach area and thigh, with the back of the upper arm if someone else injects. Novo Nordisk names the thigh, stomach and upper arm. Both say to rotate each week.
- What if I did a step in the wrong order?
- For the Lilly pens, the sheet says to throw that pen away and use a new one. Call your clinic or pharmacy if you are unsure.
- Does this page tell me how much to inject?
- No. Doses and schedules come from the label and your prescriber.
- Does this apply to vials or compounded products?
- No. Those have no maker instructions. See the injection instructions checklist for how to judge the instructions you are given.
Questions to ask
- Can you watch me give my first injection with my own pen?
- Which instruction sheet goes with the pen I was given?
- What do I do if the plunger or bar does not move the way the sheet describes?
- Where do I get a sharps container, and where do I take it when it is full?
- Who do I call, including after hours, if something goes wrong?
What is still unknown
- The Atlas read the Lilly instruction sheets for the Zepbound and Mounjaro pens (revised April 2026) and Novo Nordisk's Wegovy how-to page and quick start guide (December 2024). It did not read the full Wegovy instructions for use inside the prescribing information, so a detail there could differ.
- The summary of the Lilly sheet we read does not describe cleaning the skin, and the Wegovy pages do. Whether that reflects a real difference in advice or just what each sheet covers is not known, so ask your clinician.
- Makers revise these sheets, and a new version of a pen can work differently. Always use the sheet that came with your pen.
- How often people make mistakes with these pens in everyday use is not known.
Sources
- Zepbound single-dose pen: instructions for use Eli Lilly and Company. Revised April 2026. Company announcement, not peer reviewed
- Mounjaro single-dose pen: instructions for use Eli Lilly and Company. Revised April 2026. Company announcement, not peer reviewed
- How to take Wegovy: using the Wegovy pen Novo Nordisk, wegovy.com. Maker's patient page; the full instructions for use are part of the prescribing information package. Company announcement, not peer reviewed
- Wegovy quick start guide Novo Nordisk. Dated December 2024. Company announcement, not peer reviewed
- Zepbound (tirzepatide) injection: prescribing information Eli Lilly and Company, on DailyMed (U.S. National Library of Medicine). Label version 8/2026. Official FDA label on DailyMed
- Wegovy (semaglutide) injection and tablets: prescribing information Novo Nordisk, on DailyMed (U.S. National Library of Medicine). Label version 6/2026. One label covers both the injection and the tablets. Official FDA label on DailyMed