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
Help With Weight Loss On The NHS
The NHS offers several routes to help with weight loss, from self-help programmes to specialist services and prescription medications. Getting started depends on your BMI, health conditions, and where you live in the UK. Most weight loss journeys begin with your GP, who can assess your individual situation and point you toward the right support. Understanding your options helps you find the approach that works best for you.
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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.
NHS Weight Loss Pathways — Four Tiers Of Support
The NHS uses a four-tier system to deliver weight management support, starting with self-help and progressing to specialist services:
- Tier 1: Self-help using free digital tools, community weight management programmes, and NHS resources like the free NHS Weight Loss Plan app
- Tier 2: Primary care-based interventions delivered by your GP surgery, including behaviour change support and group programmes
- Tier 3: Specialist multidisciplinary weight management services, where prescription weight loss medication may be considered. Referral to tier 3 typically requires a GP referral, though access and waiting times vary significantly by region
- Tier 4: Bariatric surgery assessment and treatment for severe obesity with significant health complications
Most adults start at tier 1 or 2. Your GP can discuss which tier is appropriate based on your BMI, weight-related health conditions (such as type 2 diabetes, high blood pressure, or sleep apnoea), and previous weight loss attempts. Use our free BMI calculator to understand where your weight currently sits within NHS categories.
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 Medication On The NHS
Prescription weight loss medications are available through NHS tier 3 specialist weight management services. Options include GLP-1 receptor agonist medications, which are typically offered to adults with a BMI of 30 or above, or 27 or above if you have weight-related health conditions. In clinical trials, these medications have helped people lose an average of 15–21% of their body weight when combined with dietary changes and increased physical activity.
NHS access involves a clinical assessment to check the medication is suitable for you. Availability varies significantly by region and waiting lists can be lengthy. If you're interested in accessing prescription weight loss medication, ask your GP about referral to your local tier 3 weight management service. Our GLP-1 weight loss calculator can help you understand potential outcomes 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.
How do I start getting NHS weight loss help?
Begin by speaking to your GP, who will assess your health, BMI, and weight history. They can advise whether tier 1 (self-help) or tier 2 (primary care support) is suitable for you. If you have significant weight loss needs and comorbidities, your GP can refer you to tier 3 specialist services. Most GPs can also signpost you to free local weight management programmes.
What is the NHS Weight Loss Plan?
The NHS Weight Loss Plan is a free app and online programme providing 12 weeks of guidance on healthy eating, physical activity, and behaviour change. It's available to anyone in the UK and is designed as a self-help tier 1 resource. The app tracks progress and provides personalised tips. It's a good first step if you're looking to lose weight gradually.
Can I get prescription weight loss medication through the NHS?
Yes, if you meet NHS eligibility criteria (BMI ≥30, or BMI 27–29.9 with weight-related conditions) and are referred to a tier 3 specialist weight management service. However, NHS availability varies by region and waiting lists can be months to years in some areas. Private prescription weight loss medication is also available in the UK through online prescribing services.
What counts as a weight-related health condition for NHS eligibility?
Common weight-related conditions include type 2 diabetes or prediabetes, high blood pressure, high cholesterol, obstructive sleep apnoea, and cardiovascular disease history. Your GP will assess whether you have qualifying conditions. Use our BMI calculator and check your weight management context against NHS thresholds.
How much weight can I realistically expect to lose through NHS support?
This varies individually. With tier 1–2 lifestyle support (diet and exercise), sustainable loss is typically 0.5–1 kg per week, or approximately 5–15% body weight over 6–12 months. Prescription medications combined with lifestyle changes may support greater weight loss in clinical trials, but individual results vary. Track your progress with our free progress tracker.
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.