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
Best Weight Loss Programmes for UK Adults
If you're searching for the best weight loss programme, you'll find several evidence-based options available in the UK. From NHS-supported schemes to prescription weight loss medication, the right approach depends on your BMI, health conditions, and personal circumstances. Most effective weight management combines dietary changes, increased physical activity, and sometimes medical support. Our free BMI calculator can help you understand where you currently stand, and our GLP-1 weight loss calculator can show potential outcomes if prescription medication is considered. This guide covers the main evidence-based programmes available to UK adults today.
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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.
What Makes an Effective Weight Loss Programme?
The best weight loss programme combines three core elements: sustainable dietary change, regular physical activity, and behavioural support. NHS guidelines recommend losing weight at a rate of 0.5 to 1 kg per week for sustainable results. Evidence shows that even a 5% reduction in body weight delivers measurable health benefits including improved blood pressure, better blood sugar control, and reduced joint stress.
For weight management in the UK, you'll encounter these main approaches:
- Tier 1 (Self-help): Digital tools, online programmes, and community schemes. No prescription required.
- Tier 2 (Primary care): GP-supported behaviour change programmes and structured diet plans.
- Tier 3 (Specialist): Multidisciplinary weight management services, where prescription medication may be offered.
- Tier 4 (Surgical): Bariatric surgery for severe obesity with significant health complications.
Prescription weight loss medications are typically used alongside lifestyle changes, not instead of them. Results vary significantly between individuals.
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 in the UK
GLP-1 receptor agonist medications are prescription-only and require clinical assessment before prescribing. Two main options are available in the UK: Wegovy (semaglutide) and Mounjaro (tirzepatide). In clinical trials, Wegovy helped participants lose an average of approximately 15% of their body weight over 68 weeks, whilst Mounjaro showed average losses of 15–21%, though individual results vary considerably.
Access to prescription weight loss medication in the UK is available through NHS specialist weight management services (typically requiring GP referral) or through private online prescribing following a clinical assessment. Try our GLP-1 weight loss calculator to estimate potential outcomes. Always consult your GP or a licensed prescriber about whether prescription medication is appropriate for your individual circumstances.
- 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 best weight loss programme for me?
The best programme depends on your BMI, health conditions, and preferences. Start by calculating your BMI using our free tool above—this determines which NHS tier you might access. If your BMI is 30 or above (or 27+ with health conditions), you may be eligible for prescription weight loss medication. Speak with your GP about options available in your area.
How quickly will I lose weight with a weight loss programme?
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. Prescription weight loss medication may accelerate results when combined with diet and exercise, but individual outcomes vary. Faster weight loss can lead to muscle loss and isn't recommended without medical supervision.
Are prescription weight loss injections available on the NHS?
Yes, prescription weight loss medications like Wegovy and Mounjaro are available through NHS specialist weight management services, but availability varies significantly by region and there can be lengthy waiting lists. Private prescribing is also available following an online clinical assessment. Your GP can advise on NHS access in your area.
What's the difference between Wegovy and Mounjaro?
Both are prescription weight loss injections given once weekly. Wegovy (semaglutide) is a GLP-1 receptor agonist; Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist. Mounjaro showed slightly higher average weight loss in trials (~20% vs ~15%), but both require clinical assessment and both are prescription-only. Your prescriber can advise which is more suitable.
Can I lose weight without prescription medication?
Absolutely. Many people lose weight successfully through dietary changes, increased physical activity, and behavioural support programmes. The NHS Weight Loss Plan, Mediterranean diet, and structured 12-week programmes all have good evidence. Prescription medication is one option, not the only option. A combination of approaches often works best.
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.