How Wegovy and Mounjaro Differ: Active Substances and Mechanisms
The most fundamental difference lies in what each medicine actually does in the body.
Wegovy (semaglutide)
Wegovy contains semaglutide, a GLP-1 receptor agonist. GLP-1 (glucagon-like peptide-1) is a naturally occurring hormone involved in appetite regulation and the feeling of fullness. By mimicking this hormone, semaglutide acts on appetite-regulating pathways, leading many people to experience reduced hunger and what is often described as lower "food noise." Wegovy is typically started at a low dose (commonly 0.25 mg) and adjusted upward by the prescriber over time, up to the maintenance dose of 2.4 mg.
Mounjaro (tirzepatide)
Mounjaro contains tirzepatide, which acts on two receptors: both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual mechanism is what distinguishes it from semaglutide-based medicines. Mounjaro is also started at a low dose (commonly 2.5 mg) and titrated by the prescriber, with available strengths up to 15 mg.
What about Ozempic?
A related question people often ask is about the difference between Wegovy and Ozempic. Both contain semaglutide — the same active substance — but they are licensed for different indications and come in different dose ranges. Ozempic is licensed primarily for type 2 diabetes management, while Wegovy is specifically licensed for weight management. Any question about which is appropriate for you belongs with your prescriber or doctor.
How they are taken
Both Wegovy and Mounjaro are administered as once-weekly subcutaneous injections using pre-filled pens. Both carry a black triangle (▼) designation, meaning they are subject to additional monitoring. Any side effects should be reported to your healthcare professional and to your national reporting scheme (such as the UK's Yellow Card scheme).
For a deeper look at how the two medicines compare across a range of factors, see our Wegovy vs Mounjaro overview. You may also find it useful to read about the difference between Wegovy and Mounjaro in more detail, or explore what sets Wegovy and Mounjaro apart from a practical perspective.
average weekly weight change in the first 16 weeks of Mounjaro & Wegovy use*
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Whichever You Are Prescribed, GLP Trackr Tracks It
GLP Trackr is built for people already on either Mounjaro or Wegovy — the app supports both medicines fully, so your tracking experience is the same regardless of which you have been prescribed.
Because both medicines involve a titration schedule — starting low and adjusting over time under prescriber guidance — keeping an accurate log of every dose matters. The dose and injection logging feature lets you record each weekly shot: the date, dose strength, and injection site. If you are curious about how Mounjaro dose steps compare, you can also read about the difference between the 2.5 mg and 5 mg Mounjaro doses in plain language.
Beyond dose logging, GLP Trackr also lets you track side effects over time — useful given that both medicines share commonly reported effects like nausea, fatigue, and gastrointestinal changes. Logging these in the app means you arrive at prescriber appointments with a clear, organised record rather than trying to recall weeks of symptoms from memory.
Any decision about your dose, or about switching between medicines, should be made with your prescriber — never on your own. GLP Trackr helps you record your journey and supports better conversations with your healthcare team; it is not a substitute for their guidance.
Both medicines are available on iOS and Android. Download GLP Trackr on the App Store or Google Play and start a free 7-day trial — whichever pen is in your fridge, we have got you covered.
What does glptrackr include?
10+ powerful features. One app. Built specifically for Mounjaro and Wegovy users.
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Morning Check-In
Start every day with a 60-second wellness check-in. Log how you're feeling, track nausea, appetite, energy, and mood — giving you and your care team a complete picture of how your medication is working.
Injection Tracking
Log every dose with a single tap. Track your dose history, phase in your cycle, estimated medication levels, and upcoming injection dates — with reminders so you never miss a scheduled shot.
Hydration Reminders
Staying hydrated is especially important on GLP-1 medications. Set daily water targets, log intake throughout the day, and receive smart nudges when you're falling behind your goal.
Smart Meal Planning
Personalized meal plans built around your current dose phase and side effects. Every meal is GLP-1 optimized — high in protein, gentle on the stomach, and scaled to your reduced appetite.
Recipe Library
Browse 50+ high-protein, GLP-1-friendly recipes filtered by meal type, prep time, and dietary needs. Every recipe includes full nutrition info, step-by-step instructions, and tips for eating with side effects.
Progress Analytics
Beautiful, easy-to-read charts show your weight loss trajectory, weekly nutrition trends, medication responses, and wellbeing scores over time — turning raw data into genuine insights.
AI Meal Scanning
Snap a photo of any meal and get a full nutrition breakdown in seconds — calories, protein, carbs, fat, and fibre. No searching. No manual logging. Just point, snap, and track.
Exercise & Steps
Log walks, workouts, and movement with activity targets that flex with your energy levels. On lower-energy dose days, gentler targets keep you moving without burning out.
Community Support
Connect with thousands of others navigating the same medication journey. Share milestones, ask questions, find accountability partners, and get support from people who truly understand.
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Log your Mounjaro or Wegovy injection in seconds. Track your pen, your dose level, and your injection site — so you always know exactly where you are in your treatment.
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Log your weight, measurements, and how you're feeling after each dose. GLPTrackr turns your data into clear, motivating charts that show you how far you've really come.
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GLPIQ tracks where you are in your injection cycle and adjusts everything around it: lighter meals on nausea days, higher protein when appetite returns, and smarter targets as your medication level shifts.
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GLPIQ learns your personal side effect patterns over time. After a few cycles, it starts warning you the morning before a rough day — and adjusts your meal plan automatically.
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Frequently asked questions.
Wegovy contains semaglutide, a GLP-1 receptor agonist, while Mounjaro contains tirzepatide, which acts on both GLP-1 and GIP receptors. Both are once-weekly prescription injections, but their active substances and mechanisms differ. Your prescriber decides which is appropriate for you.
Both Wegovy and Ozempic contain semaglutide, but they are licensed for different purposes and come in different dose ranges. Ozempic is primarily licensed for type 2 diabetes; Wegovy is licensed for weight management. Your prescriber or doctor can advise which is relevant to your situation.
Neither can be called universally better. Which medicine is appropriate for any individual depends on their health history, other conditions, and clinical assessment. That decision belongs entirely with your prescriber or doctor, not a comparison article.
Switching between medicines is a clinical decision that must be made with your prescriber or doctor. Never start, stop, or switch a prescribed medicine without their guidance. GLP Trackr can help you log your current journey but does not advise on medication changes.
Yes. GLP Trackr supports people on both Mounjaro (tirzepatide) and Wegovy (semaglutide). You can log doses, injection sites, side effects, food, weight, and more — whichever medicine you have been prescribed.