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 Options in the UK — A Complete Health Guide
If you're looking to lose weight safely in the UK, you have more options than ever before. From free NHS support to prescription medication and specialist services, the right approach depends on your individual health, circumstances, and how much weight you need to lose. This guide covers all the evidence-based weight loss methods available, helping you understand what each option involves and how to choose the right path for you. Our free BMI calculator above can help you establish your starting point and health category.
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.
Weight Loss Methods Available in the UK
The NHS recognises weight loss as a health priority and offers a structured pathway with options at every stage. Tier 1 (self-help) includes free digital tools, community weight loss programmes like the NHS Weight Loss Plan, and online resources — ideal for those starting their weight loss journey. Tier 2 (primary care) involves your GP, behaviour change support, and structured diet programmes. Tier 3 (specialist services) provides multidisciplinary weight management teams including dietitians, psychologists, and doctors, where prescription weight loss medication may be offered. Tier 4 (bariatric surgery) is reserved for severe obesity with significant health complications. Additionally, lifestyle approaches — including calorie deficit dieting, increased physical activity, and behaviour change — remain the foundation of sustainable weight loss. Evidence shows the NHS recommends losing no more than 0.5–1 kg per week for safe, lasting results. Prescription weight loss injections like Mounjaro and Wegovy are available through specialist NHS services or privately, following clinical assessment. Our GLP-1 weight loss calculator can help you estimate potential results with prescription medication 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 weight loss method is one you can sustain long-term alongside your lifestyle. Consider your BMI and health status — those with a BMI under 27 may benefit most from lifestyle changes alone, whilst those over 30 or with weight-related health conditions may qualify for specialist support or medication. Your personal preferences and circumstances matter: some prefer structured programmes, others prefer flexibility. Time and resources influence your choice — NHS tier 1 options are free but may have waiting lists, whilst private options offer faster access. Most importantly, speak with your GP about which tier is appropriate for you. They can refer you to NHS specialist services, discuss prescription options, or recommend lifestyle programmes. Weight loss is a personal journey, and combining approaches — like adding GLP-1 medication to a reduced-calorie diet and exercise — often produces the best results. Use our progress tracker to monitor your journey whatever path you choose.
- 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 difference between NHS weight loss support and private options?
NHS support is free but may involve waiting lists; it's accessed through your GP and structured in tiers (self-help, primary care, specialist, surgery). Private options offer faster access and more choice but involve out-of-pocket costs. Both are evidence-based. Your GP can advise which suits you best.
Do I need to see my GP before trying to lose weight?
Not mandatory for lifestyle changes, but highly recommended. Your GP can assess your health, identify underlying conditions affecting weight, check if you're eligible for NHS support or prescription medication, and monitor your progress safely. This is especially important if you have other health conditions.
Can I access prescription weight loss medication like Mounjaro through the NHS?
Yes, but through specialist tier 3 weight management services, not routine GP prescription. You'll need referral from your GP and assessment by a specialist team. Eligibility requires a BMI of 30+ or 27+ with weight-related health conditions. Availability varies significantly by region. Private prescription is also available following online clinical assessment.
What's the most effective weight loss method?
Evidence shows no single "best" method — effectiveness depends on individual adherence and circumstances. Calorie deficit dieting works for weight loss, behaviour change support improves sustainability, and for those eligible, prescription medication combined with lifestyle changes produces the largest weight reductions. The most effective approach is the one you'll stick with long-term.
How quickly should I expect to lose weight safely?
The NHS recommends losing 0.5–1 kg per week as a safe, sustainable rate. This typically requires a calorie deficit of around 500 kcal daily. Faster loss is possible with medical supervision but increases muscle loss risk. Even 5–clinically studied weight loss can significantly improve health markers like blood pressure and blood sugar control.
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.