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 UK — Your Guide to Health Options
Weight loss is a realistic goal for many UK adults, whether through lifestyle changes alone or with professional support. The NHS recommends losing 0.5–1 kg per week for sustainable results, and evidence shows that even a 5–10% reduction in body weight can bring meaningful health benefits. This guide covers the main weight management options available in the UK, from self-help approaches to prescription medication, so you can understand what might work 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.
Weight Loss Methods Available in the UK
Lifestyle changes remain the foundation of sustainable weight loss. A calorie deficit of around 500 kcal per day typically supports losing approximately 0.5 kg per week. This can be achieved through dietary changes, increased physical activity, or a combination of both.
NHS weight management support is available through tier 1 and tier 2 services, including digital programmes, community groups, and GP-led interventions. Tier 3 specialist weight management services are available in some areas, where prescription weight loss medication may be considered for eligible adults.
Prescription weight loss injections are now available in the UK for eligible adults. These include GLP-1 medications like Wegovy (semaglutide), which may help reduce appetite and support feeling fuller after smaller meals. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist that may offer additional benefits. Both are prescription-only and require 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.
Who Can Access Prescription Weight Loss Treatment?
Eligibility for prescription weight loss medication in the UK typically includes adults with a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply due to higher health risks at lower weights.
Access through the NHS involves referral to a tier 3 specialist weight management service, which varies by region and can have waiting lists. Private prescription options are also available through UK-licensed online prescribers following a clinical assessment. Use our free GLP-1 weight loss calculator to explore potential outcomes, and try our BMI calculator to check where you stand.
- 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 recommended safe rate of weight loss?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable, healthy weight loss. Faster loss is possible with medical support but may increase the risk of muscle loss and nutritional deficiency. Very gradual weight management without medical supervision is not recommended.
Can I get weight loss medication on the NHS?
Yes, prescription weight loss medications are available through NHS tier 3 specialist weight management services for eligible adults. However, access varies significantly by region, and waiting lists can be lengthy. Your GP can refer you to your local specialist service for assessment.
What is the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is licensed in the UK specifically for weight management at doses up to 2.4 mg. Ozempic is licensed for type 2 diabetes (up to 2 mg) and is not approved for weight loss. Using Ozempic for weight loss would be off-label use.
How effective are prescription weight loss injections?
Clinical trials show significant results. Wegovy (semaglutide) supported an average weight loss of around 15% of body weight in STEP trials. Mounjaro (tirzepatide) showed average weight loss of 15–21% across SURMOUNT trials. Individual results vary, and medications work best alongside dietary changes and physical activity.
What health benefits can I expect from weight loss?
Even a 5–10% reduction in body weight can lower blood pressure, improve blood sugar control, reduce joint pain, lower cholesterol, and reduce sleep apnoea severity. Weight loss also reduces the risk of type 2 diabetes, cardiovascular disease, and certain cancers linked to excess 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.