The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Weight Loss Apps in the UK — How to Choose the Right One
Weight loss apps can be a practical tool to support your weight management journey, helping you track calories, monitor progress, and stay motivated. The best app depends on your goals, whether you're managing weight through lifestyle changes alone or alongside prescription weight loss medication. The NHS recommends combining dietary changes with increased physical activity for sustainable results, and many apps help make this easier by tracking both. This guide covers the main types of weight loss apps available in the UK and how they fit into your health plan.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Types of Weight Loss Apps Available in the UK
Several categories of weight loss apps are available to UK users, each serving different purposes:
- Calorie trackers (MyFitnessPal, Lose It!, Cronometer) — Log food and drink to monitor daily calorie intake and macronutrients. Most have UK food databases.
- Meal planning apps (Mealime, Gousto, HelloFresh) — Plan meals and manage shopping lists aligned with healthy eating goals.
- Exercise and fitness apps (Couch to 5K, Strong, Nike Training Club) — Build activity into your routine with guided workouts.
- Behaviour change apps (Noom, Eight Sleep) — Focus on habit formation and psychological approaches to sustainable weight management.
- NHS-aligned apps (NHS Weight Loss Plan via app partners) — Free or low-cost apps designed specifically to align with NHS guidance.
Many people find success using a combination of apps — for example, a calorie tracker plus an exercise app. If you're using prescription weight loss medication such as GLP-1 injections like Mounjaro or Wegovy, tracking weight and intake can help you monitor your response.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Choosing an App That Works for You
The best weight loss app is one you'll actually use consistently. Consider these factors:
- UK data focus — Does the app have UK food data and measurements in stone/pounds and kilograms?
- Cost — Free apps with in-app purchases, subscription apps (£3–£10/month), or one-time purchase apps.
- Features you'll use — Do you need barcode scanning, community support, workout integration, or meal planning?
- Privacy — Check data handling policies, especially for health information.
- Offline capability — Some apps work without internet, helpful for logging on the go.
Start with a free trial or free version before committing to paid subscriptions. Many users also benefit from using our free BMI calculator and progress tracker on MyWeightCheck alongside a dedicated app — they complement each other well. The combination of tracking tools, NHS weight loss guidance, and potentially prescription medication (if appropriate for you) creates the strongest foundation for sustainable weight management.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Are weight loss apps effective on their own?
Weight loss apps are most effective when combined with actual dietary changes and increased physical activity. An app alone won't create weight loss — it's a tracking and motivation tool. The NHS recommends using apps as part of a broader lifestyle approach. Apps that encourage behaviour change (like journaling or goal-setting) tend to have better outcomes than simple calorie counters.
Can I use a weight loss app if I'm taking Mounjaro or Wegovy?
Yes, absolutely. Many people using prescription weight loss medication like Mounjaro (tirzepatide) or Wegovy (semaglutide) find it helpful to track their food intake and weight using an app. This can help you notice patterns in how the medication affects your appetite and monitor your progress. Always inform your prescriber about all your health practices.
What's the difference between free and paid weight loss apps?
Free apps typically offer basic calorie tracking and food databases. Paid versions often add features like recipe generation, meal planning, workout videos, or one-to-one coaching. For many people, a free app is sufficient. Test a free version first to see if the features suit your needs before paying.
Do UK weight loss apps include prescription medication tracking?
Some specialist apps integrate medication tracking (particularly for diabetes apps), but most general calorie and fitness apps don't have built-in fields for weight loss injections. You can manually track side effects or appetite changes in notes, or use a separate symptom tracker if helpful.
Can I use an app alongside NHS weight management services?
Yes — many people combine NHS services (through tier 3 weight management services) with personal tracking apps. Your GP or NHS weight management team may even recommend specific apps. Apps are a helpful self-monitoring tool within the broader NHS pathway for weight loss and lifestyle change.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.