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
What Does Weight Loss Surgery Cost in the UK?
Weight loss surgery in the UK ranges from £9,000 to £35,000+ depending on the procedure type and whether you access it through the NHS or privately. Bariatric surgery is typically reserved for people with severe obesity (BMI 40+) or BMI 35+ with weight-related health conditions, after other nhs weight loss and weight management uk approaches have been tried. This guide covers NHS costs, private options, and how prescription weight loss alternatives compare as part of your overall weight loss uk strategy.
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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.
Weight Loss Surgery Types and Their UK Costs
Gastric bypass: £12,000–£20,000 privately; available on NHS in tier 4 specialist centres for eligible patients.
Gastric band: £7,000–£15,000 privately; less common on NHS now due to mixed long-term outcomes.
Gastric sleeve: £9,000–£18,000 privately; increasingly popular option on NHS for severe obesity.
Duodenal switch: £18,000–£35,000 privately; specialist procedure rarely available on NHS.
NHS surgery is free at point of care but requires referral through tier 4 weight management services and a substantial waiting period — often 12–36 months depending on your region. Private surgery offers faster access (4–8 weeks) but at significant cost. Some private insurers cover bariatric surgery if clinical criteria are met.
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.
Prescription Weight Loss as an Alternative
Before considering surgery, many people explore glp-1 weight loss injections like Mounjaro or Wegovy — prescription weight loss uk options that cost £129–£320 per month privately or may be available through NHS specialist services. These weight loss injections uk work alongside diet and exercise and can help people lose 15–21% of body weight. Clinical trials show these medications deliver significant results without surgery risks. Our free BMI calculator and GLP-1 weight loss calculator can help you assess whether you might be eligible for prescription weight loss medication before pursuing surgery.
- 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.
How much does weight loss surgery cost on the NHS?
Weight loss surgery is free on the NHS, but you must be referred to a tier 4 specialist bariatric centre. You'll typically wait 12–36 months depending on regional availability and demand. Eligibility requires a BMI of 40+ (or 35+ with weight-related health conditions) and evidence of attempting supervised weight loss first.
Is private weight loss surgery more expensive than NHS?
Yes. Private bariatric surgery costs £7,000–£35,000 depending on the procedure, with faster access (4–8 weeks). NHS surgery is free but involves longer waits. Some private health insurance may cover surgery if clinical criteria are met — check your policy.
What's cheaper: weight loss surgery or prescription medication?
Prescription weight loss injections cost £129–£320/month privately (£1,500–£3,840 yearly). Surgery costs £9,000–£35,000 upfront but is a one-time cost. Medication is usually cheaper initially but ongoing. Individual circumstances vary — discuss options with your GP or a specialist.
Do weight loss injections work as well as surgery?
Clinical trials show prescription GLP-1 medications help people lose 15–21% of body weight. Surgery typically results in greater initial weight loss (40–70%) but carries surgical risks. Many people achieve excellent results with medication, diet, and exercise without surgery. Results vary individually.
How do I access weight loss surgery on the NHS?
Ask your GP for a referral to your local tier 4 bariatric surgery service. You'll be assessed for eligibility (BMI, health conditions, previous weight loss attempts). If approved, you'll join a waiting list. Private options bypass this process but require payment. Your GP can discuss which route suits you.
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.