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 Surgery London — Medication-Based Alternatives
Weight loss surgery isn't the only option for significant weight management in the UK. For adults in London and across the country seeking to lose weight, prescription medications have become an increasingly popular alternative to surgical intervention. GLP-1 receptor agonist medications like Mounjaro and Wegovy are now available through the NHS and private prescribing services, offering evidence-based weight management uk approaches. This guide explains the medication options, NHS eligibility criteria, and how to explore what might work for your individual situation.
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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 Weight Loss Medications
Three main prescription medications are currently licensed for weight management in the UK:
- Mounjaro (tirzepatide) — A once-weekly injection combining GIP and GLP-1 receptor agonist activity. Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks when combined with reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — A once-weekly GLP-1 receptor agonist injection. STEP trial data demonstrated average weight loss of approximately 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — A daily GLP-1 injection, though less commonly prescribed than Mounjaro or Wegovy.
These are prescription-only medicines requiring clinical assessment before dispensing. Individual results vary significantly based on lifestyle changes, genetics, and adherence. Our free GLP-1 weight loss calculator can help you estimate potential weight loss at different doses. Always discuss any medication option with your GP or a licensed prescriber to determine eligibility and suitability for your health profile.
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 in London
Access to weight loss medication in London differs depending on whether you pursue NHS or private prescribing. NHS route: Referral to your GP for assessment, followed by potential referral to a tier 3 or tier 4 specialist weight management service. Waiting lists vary significantly across London's integrated care systems — some areas have lengthy delays. Private route: Online consultation with a UK-licensed prescriber, assessment, and dispensing through a GPhC-registered pharmacy. Available without NHS referral and generally faster access.
Adults with a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea, may be eligible. Your GP can assess your individual eligibility. Use our BMI calculator above to check your current BMI and understand where you fall on the NHS health threshold scale.
- 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 weight loss surgery the only option available in London?
No. Prescription weight loss medications like Mounjaro and Wegovy are now widely available through both NHS and private services. Many people achieve significant weight loss with medication combined with lifestyle changes. Surgery is typically considered for those with severe obesity (BMI 40+) or those who haven't responded to other interventions. Always discuss all options with your GP.
How quickly can I access weight loss medication in London?
NHS timescales vary by area — some London boroughs have shorter waits than others. Private prescribing typically offers faster access, sometimes within days of consultation. Contact your local integrated care board (ICB) or a private prescriber for specific waiting time information.
What weight loss can I expect from GLP-1 medication?
Clinical trials show average weight loss of 15–21% of body weight over several months, though individual results vary widely. Success depends on medication dose, dietary changes, physical activity, genetics, and adherence. Results cannot be assured. Our weight loss calculator can provide estimated projections based on current evidence.
Do I need a referral from my GP to access weight loss medication privately?
No. Private online prescribers can assess you directly without an NHS referral. However, it's recommended to inform your GP about any weight loss medication you're considering, especially if you take other medications or have existing health conditions.
What's the difference between weight loss medication and weight loss surgery?
Medication works through appetite regulation and metabolic support, requiring ongoing doses and lifestyle changes. Surgery (gastric bypass, sleeve gastrectomy) physically reduces stomach capacity. Medication is non-invasive, reversible, and less risky; surgery offers more dramatic weight loss but carries surgical risks and permanent changes.
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.