How Do You Get and Use Mounjaro?

Because Mounjaro and Wegovy (semaglutide) are prescription-only medicines, the starting point is always a prescriber or doctor. They assess whether the medicine is appropriate for you, decide on your starting dose, and guide any adjustments over time. If you are wondering about the prescription process specifically, see our page on getting a Mounjaro prescription for more context.

How the injection is administered

Both Mounjaro and Wegovy come as pre-filled injection pens and are taken once a week, on the same day each week wherever possible. The injection is given under the skin (subcutaneously) — common sites include the abdomen, the front of the thigh, or the upper arm. Rotating between sites each week is generally recommended to allow the skin to recover between doses.

Your prescriber, pharmacist, or the patient information leaflet (PIL) that comes with your pen is the right place to learn correct injection technique — they can walk you through the steps for your specific device. For further detail on how these medicines act in the body once injected, the page on how Mounjaro works explains the GLP-1 and GIP mechanisms in plain language.

How do you know if you have injected correctly?

A common question — for both Mounjaro and Wegovy pens — is how to tell whether the injection went in properly. Most pre-filled pens have a viewing window or indicator that shows the dose has been delivered; your PIL will describe what a successful injection looks like for your specific device. A small amount of liquid occasionally appears at the injection site, which does not necessarily mean the dose was missed, but if you are unsure, contact your prescriber or pharmacist rather than attempting to re-dose. Logging each injection — including any concerns — gives you a clear record to discuss at your next appointment.

How do you know if Mounjaro is working?

Many people begin to notice reduced appetite or lower "food noise" within the first few weeks, though the timeline varies between individuals. Weight changes are one signal, but so are shifts in energy, sleep quality, and how satisfied you feel after meals. Progress on GLP-1 medicines is rarely perfectly linear, and what counts as "working" looks different for everyone. If you have questions about whether the medicine is having the right effect for you, your prescriber is best placed to assess that based on your full clinical picture. For guidance on how long treatment typically continues, see how long you take Mounjaro.

Feeling on Mounjaro — what is commonly reported

Many people describe reduced hunger and a calmer relationship with food. Gastrointestinal effects such as nausea, constipation, or reflux are commonly reported, particularly in the early weeks or after a dose adjustment. These often ease over time. If you experience anything severe, persistent, or worrying, contact your healthcare professional promptly — do not try to manage significant symptoms on your own.

One of the most practical things you can do once you are prescribed Mounjaro or Wegovy is keep a consistent log — and that is exactly what GLP Trackr is built for.

The app's dose and injection-site logging lets you record every shot: the date, the dose strength, and which site you used. It then tracks your rotation history and suggests your next site automatically, so you are not trying to remember where you last injected. A gentle weekly reminder means a dose is far less likely to be forgotten.

Alongside injection tracking, the side-effect log lets you note how you feel after each dose — nausea, fatigue, changes in appetite, or anything else — and surfaces patterns over time. That kind of organised record is genuinely useful to bring to a prescriber appointment, and GLP Trackr can generate a summary report for exactly that purpose.

If you are curious about what coming off Mounjaro looks like further down the line, the page on stopping Mounjaro covers what is generally understood about that process.

GLP Trackr supports both Mounjaro and Wegovy users throughout their journey. It is a tracking and journaling tool — it does not give medical advice, and any decisions about your dose or treatment should always be made with your prescriber, never on your own.

Ready to bring some structure to your weekly routine? Download GLP Trackr on the App Store or Google Play and explore it free for 7 days — your injection log, site rotation tracker, and side-effect diary are all waiting.