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
Can Lemon Juice Help Weight Loss?
Lemon juice alone is unlikely to cause significant weight loss on its own. While lemon water may support hydration and contain some beneficial compounds, sustainable weight loss in the UK requires a calorie deficit alongside lifestyle changes. If you're struggling to lose weight through diet and exercise alone, prescription weight management medication may be an option worth exploring with your GP. Our free BMI calculator can help you assess whether your weight affects your health, and our GLP-1 weight loss calculator can show you potential results with evidence-based medication options available to UK adults.
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.
Prescription Weight Loss Options Available in the UK
For UK adults struggling with weight management, several prescription weight loss medications are now available through the NHS and private services. These are clinically proven to support weight loss when combined with a reduced-calorie diet and increased physical activity:
- Mounjaro (tirzepatide) — a once-weekly injection that may help reduce appetite and food cravings. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks.
- Wegovy (semaglutide) — another once-weekly GLP-1 injection. STEP trials demonstrated average weight loss of approximately 15% body weight.
- Saxenda (liraglutide) — a once-daily injection available through some NHS services and privately.
These are far more effective than lemon juice or other home remedies. All are prescription-only and require assessment by a GP or licensed prescriber to confirm eligibility.
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.
NHS vs Private Access — How to Find Out If You're Eligible
You may be eligible for prescription weight loss medication in the UK if you have 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 sleep apnoea). Use our free BMI calculator above to check your personal BMI instantly.
NHS route: Ask your GP about referral to a tier 3 specialist weight management service. Waiting lists vary by region. Private route: Online consultations with UK-licensed prescribers are available, with prescriptions dispensed by registered pharmacies.
Your GP can discuss which option is right for you and help assess whether prescription medication, alongside lifestyle changes, is appropriate for your individual health.
- 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.
Is lemon water an effective weight loss method?
Lemon water may support hydration and overall health, but it has no proven weight loss properties on its own. Weight loss requires a calorie deficit — achieved through diet and exercise — or prescription medication combined with lifestyle changes. For sustainable results, focus on reduced-calorie eating and increased activity, not supplements or home remedies.
What prescription weight loss medications are available in the UK?
Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide) are licensed for weight management in the UK. All are prescription-only, administered as injections, and work best alongside a reduced-calorie diet and physical activity. Clinical trials show average weight loss of 15–21% body weight, though individual results vary.
How do I find out if I'm eligible for prescription weight loss medication?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions. Calculate your BMI using our free BMI calculator. Contact your GP to discuss options — they can refer you to NHS specialist services or you can pursue private consultations with licensed prescribers online.
How much does prescription weight loss medication cost in the UK?
NHS access is free but involves referral to tier 3 services and can have significant waiting times depending on your region. Private prescriptions typically cost between £129–£320 per month depending on dose and provider. Both routes require a clinical assessment before prescription.
Can I get weight loss injections on the NHS?
Yes. The NHS funds Mounjaro and other GLP-1 medications through specialist tier 3 weight management services. However, availability varies by region, and you'll need a GP referral and assessment. Private online services offer faster access if you meet eligibility criteria. Your GP can advise on NHS availability in your area.
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.