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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Private Weight Loss Surgery in the UK
Private weight loss surgery offers UK adults another option for significant weight reduction when other approaches haven't worked. Bariatric procedures like gastric bypass, gastric band, and sleeve gastrectomy are available through private providers across the UK. These are more invasive than lifestyle changes or prescription medications, but may suit people with severe obesity or serious weight-related health conditions. This guide covers what's available, costs, recovery, and how surgery compares to other weight management options including NHS-funded approaches.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Types of Private Weight Loss Surgery Available in the UK
Gastric bypass is one of the most common procedures. The surgeon creates a small pouch from the stomach and connects it directly to the small intestine, bypassing much of the stomach and part of the intestines. This reduces both how much you can eat and how many calories your body absorbs. Average weight loss is 60–70% of excess body weight.
Sleeve gastrectomy removes about 75% of the stomach, leaving a tube-shaped pouch. This reduces appetite and food intake. Average weight loss is 50–60% of excess body weight.
Gastric banding places an adjustable band around the upper stomach to create a small pouch. It's reversible but generally produces more modest results (30–50% excess weight loss) and is less commonly performed now than bypass or sleeve surgery.
Duodenal switch is more complex, combining sleeve gastrectomy with intestinal rerouting. It produces significant weight loss (60–70% of excess weight) but carries higher risks and requires lifelong nutritional monitoring.
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.
Cost, Recovery, and NHS vs Private Pathways
Private weight loss surgery in the UK costs between £8,000 and £15,000 depending on the procedure type, surgeon experience, and location. NHS-funded bariatric surgery is available but typically only for people with BMI over 40 (or BMI 35+ with serious weight-related health conditions), and waiting lists can be very long in many regions. Private surgery offers faster access but requires upfront payment or private medical insurance. Recovery typically takes 4–6 weeks for return to normal activity. All bariatric surgery requires lifelong dietary changes, vitamin supplementation, and regular follow-up monitoring by your surgeon and GP to prevent complications.
- 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 weight can you lose with private weight loss surgery?
Results vary, but gastric bypass and duodenal switch typically result in 60–70% loss of excess body weight within 18–24 months. Sleeve gastrectomy averages 50–60% excess weight loss. Results depend on the procedure, your starting weight, and how well you follow post-surgery dietary guidance. Your surgeon can discuss realistic outcomes for your individual situation.
Is weight loss surgery available on the NHS in the UK?
Yes. NHS bariatric surgery is available through tier 4 specialist weight management services, but only for people with severe obesity (BMI over 40, or BMI 35+ with serious health complications). Waiting lists vary significantly by region and can be several months to years. Your GP can refer you to your local NHS specialist service.
What are the risks of weight loss surgery?
Common risks include infection, blood clots, leaks at surgical sites, and nutritional deficiencies (requiring lifelong vitamin supplements). Rarely, people experience problems with digestion, dumping syndrome (rapid stomach emptying), or gallstones. Your surgeon will discuss specific risks before the procedure. All surgery carries some risk — your GP or surgeon can help weigh benefits against risks for your situation.
How does weight loss surgery compare to prescription weight loss medications like GLP-1 injections?
Surgery is permanent and produces more rapid, dramatic weight loss (50–70% excess weight), but carries surgical risks and requires lifelong dietary changes. GLP-1 medications like Mounjaro or Wegovy are non-invasive, produce more modest results (15–21% body weight on average), require ongoing prescription, and are reversible. Both work best alongside diet and exercise. Your GP can help decide which option suits you.
Do private surgeons in the UK need to be registered and accredited?
Yes. Look for surgeons who are registered with the General Medical Council (GMC), members of the British Obesity & Metabolic Surgery Society (BOMSS), and working at Care Quality Commission (CQC) registered private facilities. Always check credentials and ask about complication rates and long-term follow-up support before choosing a provider.
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.