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 Treatment in the UK: Your Complete Guide
Weight loss treatment in the UK is available through both NHS services and private routes, ranging from lifestyle support programmes to prescription medications like GLP-1 injections. Whether you're looking to lose weight for health reasons or managing a weight-related condition, understanding your options is the first step. This guide covers NHS pathways, prescription eligibility, and evidence-based approaches to sustainable weight management. Start by checking your BMI using our free BMI calculator to understand where you currently stand health-wise.
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.
NHS Weight Loss Pathways and Prescription Options
In the UK, weight management is supported through a four-tier NHS system. Tier 1 includes self-help digital tools and community programmes. Tier 2 provides primary care-based behaviour change support (such as the NHS Weight Loss Plan). Tier 3 is specialist weight management services where prescription weight loss medication may be offered — this is where GLP-1 weight loss medications like Wegovy (semaglutide) or Mounjaro (tirzepatide) are typically prescribed. Tier 4 covers bariatric surgery for severe obesity with significant health complications.
Access to prescription weight loss treatment on the NHS requires referral to a tier 3 specialist service from your GP. Eligibility includes adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Waiting times for NHS specialist services vary significantly by region — some areas have waiting lists of many months.
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.
Private Weight Loss Treatment and Getting Started
Private weight loss treatment is available without NHS referral through GPhC-registered online prescribing services. After a clinical assessment with a UK-licensed prescriber, prescription weight loss medications can be dispensed. Costs range from approximately £129–£320 per month depending on medication type and dose.
Regardless of route, effective weight loss combines prescription support with lifestyle changes. Our free GLP-1 weight loss calculator can help you understand potential outcomes at different doses, while our progress tracker lets you log your journey. Sustainable weight management typically targets loss of 0.5–1 kg per week. Your GP can advise on the best approach for your individual circumstances and health profile.
- 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.
What weight loss treatments are available on the NHS in the UK?
NHS weight loss treatment is available through specialist tier 3 services (referred by your GP), including behaviour change programmes, low-calorie diet support, and prescription medications like Wegovy and Mounjaro for eligible adults. GPs can also signpost you to community weight management programmes as a first step.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 kg/m² or above are eligible, or those with a BMI of 27–29.9 with weight-related health conditions (diabetes, high blood pressure, cardiovascular disease, sleep apnoea). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply due to higher health risks at lower BMI levels.
Can I get weight loss medication privately in the UK without NHS referral?
Yes. Private weight loss treatment is available through UK-licensed online prescribers following a clinical assessment. This route does not require NHS referral and is typically faster than NHS waiting lists, though medications are not free on the NHS prescription charge scheme.
How does GLP-1 weight loss medication work?
GLP-1 medications like Wegovy mimic the GLP-1 hormone, which signals fullness to your brain, reduces appetite, and slows gastric emptying. Clinical trials showed average weight loss of around 15% of body weight when combined with a reduced-calorie diet and physical activity — though individual results vary significantly.
What is the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist offering average weight loss of 15–21% in trials, while Wegovy (semaglutide) is a GLP-1-only agonist with average weight loss of around 15%. Both are prescription-only, once-weekly injections. Your prescriber will assess which is most suitable based on your health profile.
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.