How GLP-1 Injections Work for Weight Loss
GLP-1 (glucagon-like peptide-1) receptor agonists are prescription-only, once-weekly injectable medicines. Mounjaro is a dual GIP and GLP-1 receptor agonist containing tirzepatide, while Wegovy contains semaglutide and acts on GLP-1 receptors alone. Both are administered by subcutaneous injection — meaning just under the skin — typically into the abdomen, thigh, or upper arm.
These medicines are commonly described as reducing "food noise" — the persistent mental focus on food — and slowing the rate at which the stomach empties. This combination helps many people eat less without feeling deprived. It is worth noting that these effects vary from person to person; what you experience will depend on your individual response, your dose, and other factors your prescriber takes into account.
Injection sites and rotation
Rotating the injection site with each weekly dose is generally recommended to allow skin and tissue to recover between injections. Common sites include the abdomen, front of the thigh, and outer upper arm. Your prescriber or the patient information leaflet that came with your pen will give you guidance specific to your medicine. If you notice persistent redness, lumps, or irritation at an injection site, let your healthcare professional know.
For a closer look at using Mounjaro specifically as a weight-loss injection, see our guide on Mounjaro as a weight-loss injection. You can also explore weight-loss injections in general or read about how Mounjaro injections are used for weight loss for more context on the process.
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.
AI Meal Tracking. Built for GLP 1 Appetites.
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Tracking Your GLP-1 Injections with GLP Trackr
Staying consistent with a weekly injection schedule is one of the most important factors in getting the most from your treatment — and that is where GLP Trackr's injection-site tracking and rotation feature becomes genuinely useful. Each time you take your dose, you log the site you used (abdomen, thigh, or arm), and the app tracks your rotation history, suggesting which site to use next. It takes seconds, and means you never have to remember where you injected last week.
Alongside site rotation, the app's dose reminder feature helps ensure your weekly injection stays on schedule — a missed dose is easy when life gets busy. You can also log each dose with its date, time, and strength, giving you a clear record to refer back to or share with your prescriber.
For a broader overview of weight-loss injection tracking, visit our weight-loss injections hub. If your prescription came through a particular pathway, our page on injection weight loss and NHS access may also be relevant background reading.
As with all aspects of your treatment, the guidance of your prescriber or doctor matters most — they know your full medical history and are best placed to advise on your injection routine and progress. If you experience any injection-site reactions that are severe, persistent, or concern you, contact your healthcare professional promptly. Any side effects worth noting can also be reported to your national reporting scheme (such as the UK's Yellow Card scheme) and to your prescriber.
Ready to take the guesswork out of injection-site rotation? GLP Trackr logs every shot and suggests your next site automatically — available free on the App Store and Google Play, with a 7-day trial to get started.
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.
GLP-1 medicines like Mounjaro and Wegovy are typically injected subcutaneously into the abdomen, front of the thigh, or outer upper arm. Your prescriber or the patient information leaflet will confirm the recommended sites for your specific medicine.
Yes, rotating the injection site each week is generally recommended to allow the skin and tissue to recover. Reusing the same spot repeatedly can cause localised reactions. Your prescriber or patient leaflet can advise on the best rotation approach for your medicine.
Results vary considerably between individuals and depend on factors including dose, diet, activity, and overall health. Many people notice appetite changes relatively early, but meaningful weight progress typically develops over several weeks to months. Your prescriber is best placed to set realistic expectations for you.
Yes. GLP Trackr lets you log each dose with its date, time, strength, and injection site, tracks your rotation history, suggests the next site, and sends reminders so your weekly injection stays on schedule.
Mild redness or tenderness at an injection site is commonly reported and often temporary. If a reaction is severe, persistent, or worsening, contact your healthcare professional promptly. You can also report side effects to your national reporting scheme, such as the UK's Yellow Card scheme.