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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Weight Loss Options in the UK — Complete Guide
Losing weight successfully depends on finding the right approach for your individual circumstances. In the UK, you have several options available — from free NHS support and lifestyle changes to prescription medication and specialist services. This guide covers all the realistic weight loss methods available to UK adults, helping you understand how to choose the right path for sustainable, safe weight loss. Use our free BMI calculator above to establish your starting point, then explore which option might work 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.
Weight Loss Methods Available in the UK
The NHS provides a structured weight management pathway with four tiers of support, each suited to different needs and circumstances:
- Tier 1 (Self-help): Free NHS tools, digital programmes, and community weight management schemes. No GP referral needed. Ideal for BMI 25–29.9 with motivation to self-manage.
- Tier 2 (Primary care): GP-led behaviour change programmes, often delivered in group settings. Combines diet, physical activity, and psychology. Requires GP engagement.
- Tier 3 (Specialist services): Multidisciplinary weight management clinics in hospitals. May include prescription medications like Mounjaro or Wegovy. Requires GP referral; availability varies by region (ICB).
- Tier 4 (Bariatric surgery): Weight loss surgery for severe obesity (usually BMI ≥40 or ≥35 with comorbidities). Requires specialist assessment and long-term commitment.
For sustainable weight loss UK, most people start at Tier 1 or 2. Calculate your personal BMI above to see which tier might be appropriate for your starting point. Prescription weight loss medications are typically accessed through Tier 3 services, though private options are also available following online clinical assessment.
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 weight loss method depends on several factors: your BMI, any weight-related health conditions (like type 2 diabetes or high blood pressure), how much weight you need to lose, your lifestyle, and your preferences. Lifestyle changes — reduced calorie diet plus increased physical activity — remain the foundation of any approach and work best alongside professional support.
- Prefer self-guided? Start with NHS Tier 1 (free digital tools and community schemes).
- Need accountability? Ask your GP about Tier 2 programmes in your area.
- Want medication support? Discuss prescription weight loss options or specialist referral with your GP.
- Have severe obesity? Ask about bariatric surgery evaluation through your GP.
Our GLP-1 weight loss calculator can help you estimate potential outcomes with prescription medication. Whatever you choose, sustainable weight loss happens at 0.5–1 kg per week alongside lifestyle change.
- 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's the fastest safe way to lose weight in the UK?
The NHS recommends losing 0.5–1 kg per week for sustainable results. This typically requires a calorie deficit of around 500 kcal per day. Very gradual weight management (>1.5 kg/week) risks muscle loss and nutrient deficiency. Prescription medications like Mounjaro or Wegovy, used alongside diet and exercise, may support faster results under medical supervision — but safe, lasting weight loss still takes time.
How do I access NHS weight loss support?
Start by speaking to your GP about weight management. They can refer you to Tier 2 programmes (behaviour change groups) or Tier 3 specialist services if appropriate. Many areas also offer free Tier 1 digital programmes and community schemes without referral. Availability varies by region (ICB). Your GP can check what's available locally and whether you're eligible based on your BMI and health conditions.
Are prescription weight loss injections available on the NHS?
Mounjaro and Wegovy are available through NHS Tier 3 specialist weight management services in some regions, but access is limited and waiting lists can be long. Private prescription is also available following an online clinical assessment with a UK-licensed prescriber. Eligibility typically requires a BMI of 30+ or 27+ with weight-related health conditions. Your GP can advise on both NHS and private routes.
How much weight can I realistically lose with medication?
Clinical trials show GLP-1 medications like Wegovy support average weight loss of around 15% of body weight over 68 weeks. Dual GIP/GLP-1 medication (Mounjaro) showed average loss of 15–21% in trials. Results vary significantly between individuals and depend on diet, exercise, and adherence. Use our weight loss calculator to estimate potential outcomes — but remember, individual results always differ.
What if I've tried dieting and it hasn't worked?
If lifestyle changes alone haven't achieved results, discuss other options with your GP: structured behaviour change programmes (Tier 2), specialist multidisciplinary services (Tier 3), or prescription medication. Some people respond better to medication plus support than diet alone. Your GP can assess whether you're eligible for referral to specialist services or prescription weight loss treatment based on your BMI, health conditions, and previous attempts.
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.