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
Free tracker included with every download this week
Best Exercise for Weight Loss — UK Options
Exercise is important for sustainable weight loss and long-term health, but it works best when combined with dietary changes. In the UK, prescription weight management medications — such as GLP-1 injections — are also available for eligible adults. If you're struggling to lose weight through exercise and diet alone, your GP can discuss whether prescription options like Mounjaro or Wegovy might support your weight management journey. This guide covers what works, NHS eligibility, and how to find out if you qualify for treatment.
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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.
UK-Licensed Prescription Weight Loss Options
If exercise and diet haven't delivered the results you need, prescription weight management medications are available in the UK for eligible adults. The main options are:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, injected once weekly. In clinical trials, Mounjaro helped participants lose an average of 15–21% of their body weight over 72 weeks, alongside lifestyle changes.
- Wegovy (semaglutide) — a GLP-1 receptor agonist, also injected once weekly. Clinical evidence showed an average weight loss of around 15% of body weight over 68 weeks.
- Saxenda (liraglutide) — a daily GLP-1 injection, with similar evidence for weight loss support.
You're typically eligible if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. These medications are prescription-only and require a clinical assessment before being prescribed.
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 — Getting Started
NHS access is through specialist tier 3 weight management services — your GP can refer you, though waiting lists vary by region. Private access is available through online prescribing services following a clinical assessment, without needing an NHS referral.
To find out if you're eligible, start by calculating your BMI using our free BMI calculator. If you're in the eligible range, speak to your GP about prescription options available to you. They can assess your individual health, discuss benefits and risks, and recommend the best approach — whether that's NHS specialist services or private prescription routes. Weight loss medications work best when used alongside continued exercise and dietary changes, not as replacements for them.
- 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.
Is exercise alone enough to lose weight?
Exercise is crucial for health and helps create a calorie deficit, but diet is equally important. Most successful weight loss requires both dietary changes and increased physical activity. If you've been exercising regularly without seeing results, prescription weight management medication may help — discuss this with your GP.
Who can get weight loss injections on the NHS in the UK?
You're typically eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions. Access is through specialist tier 3 weight management services via GP referral. Availability varies by region, so ask your GP about services in your area and expected waiting times.
How much weight can you lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy over several months. Individual results vary significantly. These medications work best alongside exercise and a reduced-calorie diet — they're not replacements for lifestyle changes.
Can I get weight loss injections privately if the NHS waiting list is too long?
Yes. Private online prescribing services offer Mounjaro and Wegovy following a clinical assessment. You don't need an NHS referral. Costs vary by provider and dose, typically ranging from £129–£320 per month. Always check the provider is GPhC-registered and the prescriber is UK-licensed.
Do I need to keep exercising if I'm on weight loss medication?
Yes. Prescription medications work best when combined with exercise and dietary changes. Exercise provides cardiovascular benefits, helps preserve muscle mass during weight loss, and improves overall health outcomes — medication alone is not enough for sustainable results.
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.