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
Weight Loss Surgery Price and Medication Alternatives in the UK
Weight loss surgery is expensive in the UK, with private procedures costing £5,000–£15,000 or more. However, prescription weight management medications offer a more affordable alternative for many adults. The NHS provides weight loss treatment through specialist services, and private prescription options are also available. Understanding your eligibility and the different cost structures can help you decide which approach suits your health needs and budget. This guide covers prescription medication options, NHS access, and how to start a conversation with your GP about weight management in the UK.
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.
UK-Licensed Prescription Weight Management Options
Three prescription medications are licensed in the UK specifically for weight management alongside lifestyle changes. Mounjaro (tirzepatide) is a once-weekly injection that works via a dual GIP and GLP-1 mechanism; clinical trials showed average weight loss of 15–21% body weight over 72 weeks. Wegovy (semaglutide) is also a once-weekly injection using a GLP-1 mechanism; STEP trial data showed approximately 15% average weight loss. Saxenda (liraglutide) is a once-daily injection also using GLP-1 action.
- All three are prescription-only and require clinical assessment
- Individual results vary significantly
- Costs range from approximately £129–£320 per month privately, depending on dose and provider
- These are used alongside reduced-calorie diet and increased physical activity
- Eligibility requires BMI of 30 or above, or 27–29.9 with weight-related health conditions
Private prescription is available through online GPhC-registered pharmacies following a licensed prescriber assessment. NHS access is through tier 3 specialist weight management services, though availability and waiting times vary significantly by region.
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 Costs
NHS route: Referral to a specialist weight management service through your GP; no medication cost if prescribed on the NHS, but waiting lists can extend months or years in some areas. Regional variation is significant. Private route: Online consultation with a UK-licensed prescriber, prescription dispensed by a GPhC-registered pharmacy, typically £129–£320 per month depending on dose. No NHS referral needed.
Your first step is to speak with your GP about weight management in the UK. They can assess whether you meet eligibility criteria (BMI and health conditions), discuss both NHS and private options, and help you understand what suits your situation. Use our free BMI calculator above to check where you stand, and try the GLP-1 weight loss calculator to see projected outcomes with prescription medication at different doses.
- 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 on the NHS in the UK?
No. The NHS offers weight management through tier 3 specialist services, including dietary support, behaviour change programmes, and in some cases, prescription medications like Mounjaro or Wegovy. Bariatric surgery is available for severe obesity with serious health complications, but medication and lifestyle support are tried first.
How much does weight loss medication cost privately in the UK?
Private prescription weight loss medications typically cost £129–£320 per month depending on the medication, dose, and provider. Mounjaro and Wegovy are usually in this range. NHS prescription has no direct medication cost, but you may wait several months for assessment.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or BMI of 27–29.9 with at least one weight-related health condition (type 2 diabetes, high blood pressure, cardiovascular disease, etc.), may be eligible. Lower thresholds apply for South Asian, Chinese, Black African, or Black Caribbean adults. Your GP or prescriber will assess individual eligibility.
How does prescription weight loss medication compare to surgery in terms of effectiveness?
Clinical trials show prescription medications achieve average weight loss of 15–21% body weight. Bariatric surgery typically results in greater weight loss (30–50%+) but carries surgical risks and irreversibility. Medication is less invasive, reversible, and suitable for moderate to severe obesity without serious complications. Your prescriber can discuss which approach suits your situation.
Can I get weight loss medication through the NHS without a long wait?
NHS access varies significantly by region and local ICB (integrated care board) availability. Some areas have shorter waits; others have waiting lists extending beyond a year. Speak to your GP about your local tier 3 service. Private prescription offers faster access but involves direct costs.
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.