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
Lemon in Warm Water for Weight Loss — What the Evidence Shows
Lemon in warm water is often promoted as a weight loss remedy, but the scientific evidence doesn't support it as an effective standalone solution. While lemon water is a healthy, calorie-free drink that may support hydration, sustainable weight loss requires a calorie deficit combined with lifestyle changes. For UK adults struggling with excess weight, prescription weight management options are now available through the NHS and private services. Understanding what actually works — from dietary approaches to evidence-based medication — can make the real difference in your weight loss journey.
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.
UK-Licensed Prescription Weight Loss Options
If you're looking for proven weight management support in the UK, prescription GLP-1 medications are available for eligible adults. Three medicines are currently licensed for weight loss:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed participants lost an average of 15–21% of their body weight alongside a reduced-calorie diet and exercise.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. STEP trials demonstrated average weight loss of around 15% over 68 weeks.
- Saxenda (liraglutide) — a daily GLP-1 injection with evidence for modest but sustainable weight loss.
All three are prescription-only medicines requiring a clinical assessment. You're eligible if your BMI is 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Try our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and use our BMI calculator to check your current BMI status.
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.
Getting Weight Loss Support — NHS vs Private
In the UK, you can access prescription weight loss medication through two routes. The NHS route involves asking your GP for a referral to a specialist tier 3 weight management service. Availability and waiting times vary significantly by region — some areas have lengthy lists. The private route offers faster access: you can have an online consultation with a UK-licensed prescriber, and if approved, the prescription is dispensed by a GPhC-registered pharmacy.
Before pursuing either route, calculate your BMI and discuss your health goals with a healthcare professional. Real, lasting weight loss combines medication (if eligible) with reduced-calorie eating and increased physical activity. Track your progress using our free progress tracker — logging your weight regularly helps you stay motivated and spot patterns.
- 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.
Does lemon water actually help you lose weight?
Lemon water is calorie-free and supports hydration, which is helpful for overall health. However, no scientific evidence shows lemon water itself causes weight loss. Weight loss requires a calorie deficit. Drinking lemon water instead of sugary drinks can help reduce calorie intake, but the lemon isn't doing the work — the calorie reduction is.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections licensed for weight loss in the UK. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with slightly higher average weight loss (15–21%) in trials. Wegovy (semaglutide) is a GLP-1 agonist with average weight loss around 15%. Both require a prescription and clinical assessment. Individual results vary significantly.
Can I get weight loss medication through the NHS?
Yes. Ask your GP for a referral to a specialist weight management service (tier 3). Eligibility requires BMI 30 or above, or 27+ with weight-related health conditions. Availability and waiting times vary by region. Some people access medication privately for faster access while others pursue the NHS route.
What's the safe rate of weight loss?
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. Faster weight loss is possible with medication support but should only be pursued under medical supervision to protect muscle mass and overall health.
Which prescription weight loss medication is best?
The best option depends on your individual health, BMI, any comorbidities, and personal preference. A GP or prescriber will assess you and recommend what's suitable. Our free BMI calculator and GLP-1 weight loss calculator can help you understand your starting point and explore options before speaking with a healthcare professional.
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.