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 Injections on the NHS — Your Options Explained
If you're looking for weight loss support through the NHS, injections are one option available through specialist services. In the UK, prescription weight loss injections like Mounjaro (tirzepatide) and Wegovy (semaglutide) are licensed for weight management in adults with a BMI of 30 or above, or 27 or above with weight-related health conditions. However, the NHS weight management pathway includes multiple approaches beyond injections. This guide covers all your options, how to access them, and how to find the right approach for your situation.
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.
The Full NHS Weight Loss Pathway — What's Available
The NHS offers structured support across four tiers designed to match the level of specialist intervention you need. Most people start with tier 1 self-help resources and community support, which includes the NHS Weight Loss Plan, physical activity programmes, and digital tools like our free BMI calculator and weight loss projection calculator. Tier 2 involves primary care intervention — your GP may refer you to a local weight management programme combining behaviour change support and nutritional guidance.
Tier 3 is specialist weight management services, where prescription medications are considered. This is where weight loss injections (Mounjaro, Wegovy, and Saxenda) are typically initiated, alongside dietary advice and physical activity plans. Tier 4 involves surgical options like gastric bypass or gastric band for severe obesity with significant comorbidities.
Access varies significantly by region — your local Integrated Care Board (ICB) determines funding and availability. Waiting lists can extend from months to years in many areas, which is why some people also explore private prescription options.
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.
Choosing the Right Weight Loss Approach for You
The best approach depends on your BMI, health conditions, lifestyle, and preferences. Use our free BMI calculator to establish your current category, then consider: Do you want to start with lifestyle changes alone? Most NHS services recommend this first. Are you struggling with appetite control or emotional eating? Prescription injections may help. Do you have significant mobility issues or multiple weight-related conditions? Specialist tier 3 services might be appropriate. Your GP can assess your individual situation and refer you to the right level of support. If NHS waiting lists are very long in your area, discuss whether private prescription options are right for you alongside lifestyle changes.
- 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 injections are available on the NHS?
Three GLP-1 medications are licensed for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections; Saxenda is a daily injection. All are prescription-only and typically prescribed through NHS tier 3 specialist weight management services.
How do I access weight loss injections through the NHS?
Ask your GP for a referral to your local tier 3 specialist weight management service. They'll assess whether you're eligible (usually BMI 30+, or 27+ with health conditions), discuss your health history, and create a treatment plan. NHS access is free but availability varies significantly by region and waiting times can be lengthy.
What if the NHS waiting list is too long?
Private prescription weight loss injections are available through UK-licensed online prescribers. These require a private clinical assessment and prescription, then dispensed by a regulated pharmacy. Costs range from approximately £129–£320 monthly depending on dose. Always combine injections with lifestyle changes regardless of route.
Are there effective weight loss options besides injections?
Yes — sustainable weight loss UK typically combines dietary changes (like reducing calories by 500 kcal daily), increased physical activity, and behaviour change support. NHS tier 1 and tier 2 services offer free resources and programmes. Many people achieve significant results with lifestyle changes alone, supported by our free progress tracker.
Will a weight loss injection work for me?
Results vary considerably between individuals. Clinical trials show injections help most people lose weight when combined with reduced calories and increased activity, but outcomes aren't assured. Your prescriber will assess your suitability based on your medical history, current medications, and health conditions. Use our GLP-1 weight loss calculator to explore projected outcomes at different doses.
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.