Online Weight Loss Injections: What You Need to Know If You're Already Prescribed

Mounjaro and Wegovy are once-weekly injectable medicines that work on appetite-regulating pathways in the body. Mounjaro's active substance is tirzepatide, a dual GIP and GLP-1 receptor agonist; Wegovy's active substance is semaglutide, a GLP-1 receptor agonist. Both are supplied as pre-filled pens and are typically started at a low dose, with any adjustments made by your prescriber over time — not independently.

These medicines are only available with a valid prescription from a registered healthcare professional. Some people obtain their prescription through an online prescribing service; others through a clinic or another route. Either way, the medicine itself arrives as the same pre-filled pen, and the practical experience of injecting, rotating sites, and logging doses is the same regardless of how you got there.

Common injection sites

The three most widely used injection sites are the abdomen, the front of the thigh, and the upper arm. Rotating between sites — rather than injecting into the same spot repeatedly — is generally recommended to support skin health and consistent absorption. Your prescriber or the patient information leaflet that came with your pen will guide you on technique; the important habit to build is keeping a clear record of where you injected last.

For more context on how these medicines are typically prescribed and what the different dose stages look like, the page on weight loss injections covers the broader picture. If you have questions about what different access routes typically involve, the guide to getting weight loss injections online explores that in more detail.

Once you are prescribed and injecting, the practical challenge is consistency — remembering which site you used last, whether you took this week's dose, and what your body has been doing since you started. That is exactly what GLP Trackr is built for.

The app's injection-site tracking and rotation feature lets you log each injection — recording the site, the dose strength, and the date — and then suggests your next rotation automatically. Over weeks, this builds a clear picture of your injection history without you having to remember it. Paired with dose reminders, it means a weekly dose is far less likely to be missed or double-counted.

Alongside injection tracking, the daily check-in lets you log how you are feeling — energy, mood, any side effects — so that if you notice a pattern around injection day, you have a record to bring to your next prescriber appointment rather than trying to recall it from memory. This is particularly useful if you are managing your prescription through an online service where appointments may be less frequent.

If you are also curious about what the medicine typically costs through different routes, the page on weight loss injection pricing sets out what factors are generally involved — without quoting figures that change frequently.

GLP Trackr is a tracking and journaling companion — it does not replace your prescriber or provide medical advice. Any questions about your dose, your injection technique, or whether this medicine is right for you should always go to your healthcare professional. If you experience any symptoms that are severe, persistent, or concern you, contact your prescriber or doctor promptly.

Ready to keep your injection schedule and rotation in one place? GLP Trackr is free to try for 7 days — download it on the App Store or Google Play and start logging from your very next dose.