Medically assessed by W. van Donselaar, MD, BIG 79020681301, on 20-05-2026.
Mounjaro works differently from Ozempic. It contains tirzepatide instead of semaglutide, it comes in a different pen (the Mounjaro KwikPen) and the dosing steps are different. The injection itself is similar: once a week under the skin in the abdomen, thigh or upper arm. Below you walk through everything you need to know before your first injection. If in doubt, grab the leaflet or call your doctor or our counselling service.
What do you need?
For one injection, you have the following ready to go:
- The Mounjaro KwikPen (out of the fridge when unopened)
- A disinfectant wipe for the injection site
- A needle container for the used pen
- A clean work surface
A key difference from the Ozempic pen: the Mounjaro KwikPen has the needle already built in. You don't need to screw a needle onto the pen yourself, nor do you need to order separate needles from your pharmacy. One KwikPen is intended for a single injection and you throw it away afterwards, or in some versions it contains doses for several injections. Which version you have is shown on the packaging and in the leaflet. Check that the first time you pick up a new pen so there are no surprises.
How many injections are in your box? With most strengths, you get four pens per month, one per week. With that, you cover an entire treatment month. Keep a needle container handy, which can be ordered from your pharmacy or online, as used KwikPens do not belong in normal waste.
Preparing the pen
Take the pen out of the fridge about 30 minutes before injecting. A pen at room temperature pricks more pleasantly than an ice-cold one. Check afterwards:
- Fluid view: look through the pen's viewing window. The liquid should be clear and colourless to pale yellow. Is it cloudy, discoloured or contains rubbish: do not use. Call your pharmacy for a replacement
- Check expiry date: is on the side of the pen
- Remove safety cap: only pull off the grey safety cap just before injection. Not before; the pen is then ready for use and may accidentally go off
For dosage steps: Mounjaro starts at 2.5 mg per week for four weeks (habituation phase). After that, your doctor steps you up to 5 mg per week. In case of insufficient effect, the dosage can go up further to a maximum of 15 mg per week, in increments of 2.5 mg per month. What dose you get is written on the pen package and in your dosage schedule.
Giving the injection
Mounjaro inject into the following possible spots:
| Where? | How? |
|---|---|
| Belly | At least two centimetres from your navel |
| Upper leg (thigh) | Front or outside |
| Upper arm | Only if someone else puts the injection |
Steps before injection
- Clean the skin with the disinfecting wipe and let it dry
- Take a thin piece of skin between thumb and forefinger (skin fold)
- Hold the pen flat against your skin at a right angle (90 degrees)
- Press the purple activation button. You hear a first click: the injection starts
- Hang in there: wait for the second click (can take up to 10 seconds) while holding the pen steady against your skin
- Pull the pen away only after the second click. The viewport should now be grey: signal that everything has been injected
- Used pen directly into your needle container
The second click is crucial. If you remove the pen too early, you won't get your full dose. Some people find that the whole cycle takes 5-10 seconds; this is normal.
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When do you inject?
Once a week, on a fixed day. Choose a time you can stick to. The time of day (morning or evening) doesn't matter, and you don't have to combine the injection with eating or not eating. Many people choose a quiet day on the weekend. Others link the injection to a fixed time in their week, such as after brushing your teeth on Sunday evening.
Important to know: If one day is not convenient, you can still take your injection on a later day up to four days after your fixed injection day. From then on, that later day becomes your new injection day. Once the four-day limit has passed: skip the missed dose and wait for the next scheduled day. Never take two doses at once to catch up; you will get double the amount of active ingredient and more chances of side effects. When in doubt: call your doctor or our counsellor, and we will coordinate together.
Storage between injections
Store Mounjaro KwikPens in the fridge between 2 and 8 degrees before use. Once taken out of the fridge, the pen may remain at room temperature (maximum 30 degrees) for up to 21 days, out of direct sunlight.
Throw away a KwikPen that has been accidentally frozen. Freezing damages the active ingredient.
For travelling: a cooler bag with cool-pack is wise if you are travelling for more than a few days or if the destination is hot. When in doubt, call your pharmacy for advice on your situation.
First injection: practical tips
The first time is often the most exciting. A few things that help:
- Prepare everything: get everything ready before you start. The pen, the cloth, your container
- Don't decide on dosage yourself: Follow the dosage schedule given by your doctor. Do not “briefly” turn up or down
- Do it in the evening: side effects such as nausea you can then possibly sleep through
- Someone added: for the first time, a fine situation is if someone is with you, or available online
- Give it time: really wait for the second click. Rather 5 seconds longer than half a dose
Side effects in the first weeks include: nausea, diarrhoea, sometimes abdominal pain. Read the side effects of Ozempic for an overview; for Mounjaro, the pattern works similarly.
What if something goes wrong?
With a new injection, something unexpected can always happen. Most situations are not serious, but it is nice to know what to do. Here are the most common ones:
| Situation | What to do |
|---|---|
| No second click heard, pen pulled away | You probably have an incomplete dose. Call your doctor or our guidance team for advice; do not puncture again |
| Safety cap removed too early, pen activated without injection | Pen is lost. Call pharmacy for replacement |
| Strong skin reaction at injection site | Slight redness or itching is normal and will disappear on its own. Swelling, severe pain or rash: call your doctor |
| Accidentally the same pen twice | Once you throw away. The KwikPen typically gives only one injection, a second attempt would do nothing |
| Pen falls to ground after preparation | Inspect it for visible damage or cracks. If it seems whole: use it. If in doubt: call your pharmacy |
Call 112 in case of severe side effects immediately after the injection. These include breathlessness, swelling of the face or throat, or a rash that spreads rapidly. This is rare, but reason for immediate medical attention.
A course at Weightconsult: how does it work?
We supervise trajectories with Mounjaro injections entirely online. In the intake, we discuss which drug is right for you, whether it is Mounjaro, Ozempic or another GLP-1 drug. Before the first injection, you can ask questions via video or chat; we also send a short explanation with the most important steps beforehand.
In the build-up phase, the first two to three months, we have more intensive contact via online check-ins. How is habituation going, what side-effects do you notice, can the dosage be increased according to schedule. If you have questions in between, you can always contact us via chat. This is not an extra-cost moment, but part of the process. Delivery of your KwikPen goes via pharmacy eFarma after a valid prescription. We arrange your follow-up prescriptions automatically as long as the route is running and the evaluations are going well.
Key points blog at a glance
Do I need a separate needle for Mounjaro?
Do I need a separate needle for Mounjaro?
No. The KwikPen already has the needle built in. Do not order separate needles.
How many injections are there in one KwikPen?
How many injections are there in one KwikPen?
For most variants, a KwikPen is a single injection. Some dosage forms deliver more doses per pen; check the packaging and leaflet.
Why do I have to wait for two clicks?
Why do I have to wait for two clicks?
The first click is the signal that the injection has started. The second click confirms that the full dose has been delivered. Between those two clicks is the actual injection; removing it too early gives an incomplete dose.
Can I combine Mounjaro with other medications?
Can I combine Mounjaro with other medications?
Discuss this with your doctor. With diabetes medication such as insulin or a sulphonylurea derivative, a dose adjustment may be needed due to risk of low blood sugar. Other medications can often continue as normal, but your doctor will assess this on a situation-by-situation basis.
What do I do in case of forgotten injection?
What do I do in case of forgotten injection?
Within four days of your regular injection day, you may still prick. After that, skip and resume on the next scheduled day. Never take two doses at once.