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 in the United Kingdom — Complete Guide
Weight loss in the United Kingdom is a significant health priority, with around 63% of UK adults now overweight or obese. If you're looking to lose weight, the NHS provides a clear pathway of support from self-help through to specialist interventions. This guide covers evidence-based weight management strategies, NHS weight loss programmes, and the prescription weight loss options now available to eligible UK adults, including GLP-1 weight loss injections. Whether you're starting your weight loss journey or exploring medical options, understanding what's available and what works is essential.
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 Support and Safe Strategies
The NHS weight management pathway is structured in four tiers, designed to support people at different stages. Tier 1 includes self-help resources and digital tools — like our free BMI calculator and weight converter — which help you understand your current weight and set realistic targets. Tier 2 involves primary care support through your GP, who may recommend structured behaviour change programmes such as the NHS Weight Loss Plan.
- Safe weight loss rate: 0.5 to 1 kg per week is recommended by the NHS
- Calorie deficit needed: approximately 500 kcal per day for 0.5 kg weekly loss
- Even 5–clinically studied weight loss can reduce blood pressure, improve blood sugar control, and lower cholesterol
- Sustainable approaches combine dietary changes with increased physical activity
For weight management in the UK, consistency matters more than speed. Using our free progress tracker can help you log your journey and stay motivated over time.
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 Options Available in the UK
Prescription weight loss medications are now available through the NHS and private prescribing for eligible UK adults. These include GLP-1 weight loss injections such as Wegovy (semaglutide) and Mounjaro (tirzepatide), which work by regulating appetite and helping you feel fuller after smaller meals. Access through the NHS is via specialist tier 3 weight management services — typically requiring a GP referral — though private prescribing is also available following an online clinical assessment.
- Eligible if BMI ≥30, or ≥27 with weight-related health conditions
- Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults
- Clinical trials showed average weight loss of 15–21% body weight alongside lifestyle changes
- Prescription-only — prescribed after assessment by a licensed healthcare professional
Try our GLP-1 weight loss calculator to explore potential outcomes at different doses.
Choosing the right approach depends on your individual circumstances, health history, and weight loss goals. Use our free BMI calculator to establish your starting point — this helps your GP or prescriber assess whether you're eligible for specialist support. Most effective weight loss combines dietary changes, increased physical activity, and behaviour change, with medication used as an additional tool rather than a replacement for lifestyle modifications.
- NHS Tier 3 services offer multidisciplinary support: dietitians, psychologists, and doctors working together
- Waiting times for NHS specialist services vary by region — some areas have significant delays
- Private weight loss medication is available without NHS referral but costs apply
- Bariatric surgery (Tier 4) is available for severe obesity with significant health complications
Whatever your chosen path, tracking progress with our free progress tracker helps maintain motivation and identify what's working for you.
- 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 is the fastest safe weight loss rate in the UK?
The NHS recommends losing no more than 0.5 to 1 kg (1 to 2 lbs) per week for safe, sustainable weight loss. Faster loss is possible under medical supervision but increases the risk of muscle loss and nutritional deficiencies. Very gradual weight management (more than 1.5 kg per week) should only be attempted under close healthcare professional guidance.
How can I access weight loss medication on the NHS in the UK?
NHS prescription weight loss medication is available through specialist tier 3 weight management services. You'll typically need a GP referral to access these services. Eligibility requires a BMI of 30 or above, or 27 or above with weight-related health conditions. Availability and waiting times vary significantly by region.
What's the difference between Wegovy and Ozempic for weight loss?
Both contain semaglutide, but Wegovy is specifically licensed for weight management in the UK at doses up to 2.4 mg weekly. Ozempic is licensed for type 2 diabetes only at doses up to 2 mg. Using Ozempic for weight loss is off-label prescribing. Wegovy is the appropriate licensed medication for weight loss in UK adults.
Can I lose weight without prescription medication?
Yes — many people lose weight successfully through lifestyle changes alone. A calorie deficit of around 500 kcal per day typically results in 0.5 kg weekly loss. The NHS Weight Loss Plan, behaviour change programmes, and structured dietary approaches all support sustainable loss without medication. Medication is an additional option for eligible people, not a requirement.
What health benefits can I expect from losing 10% of my body weight?
Even modest weight loss of 5–10% can reduce blood pressure, improve blood sugar control, lower LDL cholesterol, reduce joint pain, improve sleep apnoea severity, and lower your risk of type 2 diabetes and certain cancers. These benefits often appear within weeks of starting weight loss, before reaching your goal weight.
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.