Understanding the Options: Mounjaro and Wegovy
The two most widely discussed prescription weight loss injections are Mounjaro (active substance: tirzepatide) and Wegovy (active substance: semaglutide). Both are administered once a week via a pre-filled pen, and both are prescription-only medicines — meaning they can only be obtained through a prescriber and a registered pharmacy.
How they differ mechanically
Wegovy works by activating GLP-1 receptors, which are involved in regulating appetite and the feeling of fullness. Mounjaro activates both GLP-1 and GIP receptors — making it a dual receptor agonist. What this means in practice for any individual is something only their prescriber can assess, taking into account their full medical history.
What they have in common
- Both are started at a low dose and adjusted over time, with the schedule set by the prescriber
- Both are associated with commonly reported side effects including nausea, digestive discomfort, and fatigue
- Both carry additional monitoring requirements — any side effects should be reported to your healthcare professional and to your national reporting scheme (such as the UK's Yellow Card scheme)
- Neither is suitable for everyone; suitability is a clinical decision
If you are weighing up the differences between these two medicines, our guide comparing weight loss injection options covers the factual distinctions in more detail, and our page on which weight loss injection is considered safest looks at the safety considerations people commonly ask about. For a broader overview of how these injections work, visit our weight loss injections hub.
The question of which is "best" cannot be answered without knowing your individual circumstances. A prescriber who knows your health history is the only person positioned to make that call.
average weekly weight change in the first 16 weeks of Mounjaro & Wegovy use*
Tracking the right four numbers — weight, waist, protein and dose — turns a noisy chart into a clear story. That's the loop GLP-1 users keep coming back for.
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Already Prescribed? Here Is How GLP Trackr Helps You Get the Most from Your Journey
Once you are prescribed a weight loss injection — whichever one your doctor has chosen for you — staying consistent with your weekly schedule is one of the most important things you can do. GLP Trackr is built specifically for people already on Mounjaro or Wegovy, and its injection-site tracking feature is where many users start.
Each time you inject, you can log the site (abdomen, thigh, or upper arm), and the app tracks your rotation history so it can suggest where to inject next. Rotating sites properly is something your prescriber will have mentioned, and having an automatic record removes the guesswork entirely.
Beyond site rotation, the app logs each dose date and strength, and sends gentle reminders so a weekly injection is never accidentally missed. If you ever experience side effects — nausea, fatigue, digestive changes — the side-effect tracker lets you record how you feel day to day, building a clear picture you can bring to your next appointment.
GLP Trackr supports both Mounjaro and Wegovy users, so whichever prescription you have, the tools are there from day one. You can also explore what makes a weight loss injection effective for more context on what to track and observe during your journey.
A note on safety: if you experience any side effects that feel severe, persistent, or concerning, contact your healthcare professional promptly. GLP Trackr helps you record what you are experiencing so you can discuss it with your prescriber — it is not a substitute for their guidance, and any decisions about your dose or treatment always rest with them.
Ready to track your injection schedule in one place? Download GLP Trackr on the App Store or Google Play — your first seven days are completely free.
What does glptrackr include?
10+ powerful features. One app. Built specifically for Mounjaro and Wegovy users.
Everything your GLP-1 journey needs. Free to try for 7 days.
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.
Never Forget a Dose Again.
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.
Watch Your Body Transform, Week by Week.
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.
You're Not on This Journey Alone.
Connect with thousands of real GLP-1 users sharing their wins, side effect tips, and meal ideas. Get the support of people who truly get it — because they're living it too.
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The Most Advanced GLP-1 Brain Ever Built.
The first AI built exclusively for GLP-1 weight loss. Every insight, every meal plan, every prediction trained on one thing only: helping you get the most out of your medication.
Knows Your Cycle
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.
Predicts Before You Feel It
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.
Finds Your Golden Dose
GLPIQ analyses every dose you've been on: weight loss rate, side effects, food noise, mood, protein adherence and tells you which dose gave you the best results. No other app does this.
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Frequently asked questions.
There is no single "best" option — the right injection depends on your individual health, medical history, and what your prescriber recommends. Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only medicines, and suitability is a clinical decision made by your doctor.
Mounjaro (tirzepatide) activates both GLP-1 and GIP receptors, while Wegovy (semaglutide) activates GLP-1 receptors only. Both are once-weekly injections started at a low dose and adjusted by the prescriber. Which is appropriate for you is a decision for your healthcare professional.
Your prescriber decides which medicine is appropriate based on your health history and clinical needs. You can discuss your preferences with them, but the final decision rests with the clinician who knows your full medical picture.
Yes. GLP Trackr supports users on both Mounjaro and Wegovy. You can log your injection sites, track dose dates, set weekly reminders, and record side effects regardless of which medicine you have been prescribed.
Log how you feel in GLP Trackr to track patterns over time, and discuss any side effects with your prescriber or doctor. If symptoms are severe, persistent, or worrying, contact a healthcare professional promptly rather than waiting for a scheduled appointment.