What Is the Name of the Weight Loss Injection?

When people search for "the weight loss injection", they are almost always referring to one of these two medicines. Here is a factual overview of each.

Mounjaro (tirzepatide)

Mounjaro is the brand name; tirzepatide is the active substance. It is a dual GIP and GLP-1 receptor agonist, meaning it acts on two appetite-related hormone pathways. It is given as a once-weekly subcutaneous injection using a pre-filled pen. Dose strengths commonly associated with Mounjaro include 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg, with the starting dose and any adjustments decided entirely by a prescriber.

Wegovy (semaglutide)

Wegovy is the brand name; semaglutide is the active substance. It is a GLP-1 receptor agonist, acting on one appetite-related hormone pathway. Like Mounjaro, it is a once-weekly subcutaneous injection delivered via a pre-filled pen. Dose strengths commonly associated with Wegovy include 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg, again with the titration schedule set by the prescriber.

What they have in common

• Both are prescription-only medicines — a prescriber decides suitability, not the individual
• Both are injected under the skin (subcutaneously) once a week
• Both work on appetite-regulating pathways, with many people reporting a reduced sense of hunger
• Both carry a black triangle (▼) designation in some markets, meaning side effects should be reported to your national reporting scheme (such as the UK's Yellow Card scheme) and to your healthcare professional
• Neither is insulin, and neither is a cosmetic quick fix

You can read a broader overview on our guide to weight loss injections, or explore related questions such as what is the name of the new slimming injection and what is the name of injection for weight loss for more background.

Once you have been prescribed either Mounjaro or Wegovy, keeping track of your weekly injections — which site you used, which dose, and when — quickly becomes an important part of staying consistent. GLP Trackr is built specifically for this.

The app's injection-site tracking and rotation feature lets you log each injection (abdomen, thigh, or upper arm), then suggests your next site automatically, so you never have to guess or try to remember where you injected last week. Alongside this, dose logging records the date, time, and dose strength of every shot in one place — giving you a clear, timestamped history you can bring to your prescriber appointments. Gentle dose reminders mean a weekly injection is far less likely to slip your mind.

If you are curious about other aspects of your treatment — such as the costs associated with weight loss injections — the app does not cover pricing, but it does help you stay consistent with what you have been prescribed, so nothing goes to waste.

GLP Trackr supports both Mounjaro and Wegovy users, wherever in the world they are. It is available free on the App Store and Google Play, with a 7-day trial so you can see whether it fits your routine before committing.

Ready to keep every injection logged and your rotation on track? Download GLP Trackr on the App Store or Google Play and start your free 7-day trial today.

Any questions about your dose, injection technique, or whether these medicines are right for you should always be directed to your prescriber or doctor — they know your full medical history and are the right person to guide those decisions.