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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Best Workout Apps for Weight Loss in the UK
Fitness apps can be a great tool for supporting your weight management journey, but sustainable weight loss requires both exercise and diet changes. In the UK, prescription weight loss options like Mounjaro and Wegovy are now available for eligible adults alongside lifestyle changes. This guide explores effective workout apps and explains how prescription weight management fits into your overall approach to achieving a healthy weight.
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Calculate Your BMI Instantly
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.
Workout Apps vs. Prescription Weight Management
Fitness apps are excellent for tracking exercise and building consistent workout habits, but they work best when combined with other weight management strategies. While apps like Couch to 5K, MyFitnessPal, and Strong can help you increase physical activity and calorie expenditure, nhs weight loss guidance emphasises that sustainable results come from a combination of diet, exercise, and sometimes medical support.
In the UK, prescription weight loss medication is now available through the NHS and private providers for adults who meet eligibility criteria. Options include:
- Mounjaro (tirzepatide) — a weekly injection that may help reduce appetite and support weight loss alongside exercise
- Wegovy (semaglutide) — another once-weekly GLP-1 injection licensed for weight management in UK adults
- Saxenda (liraglutide) — a daily injection option also available in the UK
These medications work by helping regulate appetite and can make dietary changes and exercise more sustainable. Clinical trials show that when combined with reduced-calorie diet and increased activity, these medications may help participants lose significantly more weight than lifestyle changes alone. Try our free GLP-1 weight loss calculator to explore potential outcomes if medication is prescribed to you.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
NHS vs Private Access and Eligibility
NHS access: Weight loss medication is available through specialist tier 3 weight management services, typically accessed via GP referral. However, availability varies significantly by region and waiting lists can be lengthy in many areas. Your GP can assess whether you're eligible and refer you to a local service.
Private access: Prescription weight loss medication is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. No NHS referral is needed, though costs vary by dose.
Eligibility: Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (such as type 2 diabetes, high blood pressure, or sleep apnoea), may be eligible. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply. Check your BMI using our free BMI calculator above, then discuss options with your GP or a licensed prescriber to see if prescription weight loss medication is right for you.
- 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.
Can I use just a workout app to lose weight?
Workout apps are valuable for building exercise habits and increasing calorie burn, but the NHS emphasises that sustainable weight loss requires both dietary changes and physical activity. Apps help with the exercise component, but diet is typically more important for weight loss. For some people, prescription weight loss medication can make both diet and exercise changes easier to maintain.
What's the difference between Mounjaro and Wegovy?
Both are GLP-1 receptor agonist injections licensed for weight management in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist given once weekly. Wegovy (semaglutide) is a GLP-1 agonist also given once weekly. Clinical trials showed different average weight loss outcomes, but individual results vary significantly. Your prescriber will recommend the most appropriate option based on your health.
How quickly can I expect to lose weight with prescription medication?
Clinical trials show weight loss typically becomes noticeable after 4–8 weeks on medication. Average weight loss with Mounjaro was approximately 15–21% of body weight over one year when combined with diet and exercise. However, results vary between individuals. Using our free weight loss calculator can help you estimate potential outcomes based on different doses.
Do I need to exercise if I'm taking weight loss medication?
Yes. Prescription weight loss medications like Mounjaro and Wegovy work best when combined with a reduced-calorie diet and increased physical activity. Medications help regulate appetite and support feeling fuller, which makes it easier to maintain these lifestyle changes. Workout apps can support your exercise routine during treatment.
How do I find out if I'm eligible for weight loss medication in the UK?
Start by calculating your BMI using our free BMI calculator on this page. If your BMI is 30 or above (or 27–29.9 with a weight-related health condition), speak to your GP about weight management options. They can refer you to NHS specialist services or discuss private prescribing if that's more accessible in your area.
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.