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 Available in the UK
If you're considering a contraceptive pill specifically for weight loss, it's important to know that while some contraceptives may have different effects on weight than others, weight management in the UK typically involves a range of approaches. These span from lifestyle changes and free NHS support through to specialist services and prescription medications. Understanding your options helps you and your GP choose the most effective path for sustainable weight loss.
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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 Approaches in the UK — From Self-Help to Specialist Care
The NHS uses a tiered approach to weight management, starting with self-help and progressing to specialist care. Tier 1 includes free resources like the NHS Weight Loss Plan, digital tools, and community weight management programmes — many available without GP referral. Tier 2 involves primary care support: your GP can discuss lifestyle changes, recommend evidence-based diets like the Mediterranean approach, or refer you to behaviour change programmes. Tier 3 is specialist multidisciplinary weight management services, where prescription weight loss medications like Mounjaro and Wegovy may be offered alongside dietitian support. Tier 4 covers bariatric surgery for severe obesity. For sustainable weight loss in the UK, the NHS recommends losing 0.5–1 kg per week through a combination of reduced-calorie diet and increased physical activity. Use our free BMI calculator to assess where you currently fall on NHS weight categories, and our GLP-1 weight loss calculator to explore potential outcomes with prescription medication if eligible.
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 your individual circumstances, including your current BMI, any weight-related health conditions, previous weight loss attempts, and personal preferences. Start by discussing your goals with your GP — they can assess whether you meet eligibility criteria for prescription weight loss support and help rule out underlying health conditions affecting your weight. If you have a BMI of 30 or above, or 25–29.9 with weight-related conditions like type 2 diabetes or high blood pressure, you may be eligible for NHS specialist services. Many people find success combining dietary changes with increased physical activity alongside professional support. Our progress tracker can help you log your weight loss journey and maintain motivation. Remember that sustainable weight loss takes time; rapid results often don't last.
- 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.
Can contraceptive pills actually help with weight loss?
Most contraceptive pills do not cause weight loss; some may cause modest weight gain or water retention. If weight management is your goal, discuss with your GP — they may suggest a particular formulation, but contraceptives are not prescribed primarily for weight loss. Weight loss support in the UK usually involves lifestyle changes, specialist services, or prescription weight loss medications like Mounjaro or Wegovy.
What is the fastest safe way to lose weight in the UK?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week as safe and sustainable. Faster loss is possible under medical supervision but increases muscle loss risk. Prescription GLP-1 medications like Mounjaro and Wegovy can support faster results alongside diet and activity changes, but require clinical assessment and a prescription from a licensed prescriber.
Is prescription weight loss medication available on the NHS?
Yes, tirzepatide (Mounjaro) is now approved within NHS specialist weight management services for eligible adults. Access is through tier 3 specialist services and varies significantly by region. Private prescription access is also available through licensed UK prescribers without NHS referral, though this involves private costs.
How do I know if I'm eligible for weight loss support in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea), may be eligible. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply. Your GP can assess your eligibility and discuss the options most suitable for your health.
What lifestyle changes support sustainable weight loss?
Evidence-based approaches include a calorie deficit of around 500 kcal per day (supporting ~0.5 kg/week loss), Mediterranean or low-carbohydrate diets, intermittent fasting, and regular physical activity. Even 5–clinically studied weight loss brings measurable health benefits. Combine dietary changes with support — whether from your GP, NHS programmes, or a dietitian — for best long-term results.
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.