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
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Warm Lemon Water for Weight Loss — What Works in the UK
While warm lemon water is often promoted for weight loss, the evidence for its direct effect is limited. If you're looking for effective weight management in the UK, prescription medications like Mounjaro and Wegovy have strong clinical evidence behind them. This guide covers what the science says about lemon water, and explains the prescription weight loss options available to eligible adults through NHS weight loss services or private prescribing. Check your BMI using our free calculator above to see if you might qualify for prescription support.
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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.
UK-Licensed Prescription Weight Loss Options
If you're interested in evidence-based weight management, the UK has three prescription medications licensed specifically for weight loss: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections that work by activating GLP-1 and GIP hormone pathways, which help regulate appetite and reduce food cravings. In clinical trials, Mounjaro helped participants lose an average of 15–21% of their body weight, while Wegovy showed average losses of around 15%, though individual results vary significantly. Both are prescription-only and require a clinical assessment to confirm eligibility. You may qualify if you have a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses.
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 Help: NHS vs Private Routes
In the UK, you can access prescription weight loss medication through two main routes. NHS access is through specialist tier 3 weight management services — ask your GP for a referral, though waiting times vary significantly by region and availability can be limited. Private access is available through registered online prescribers following a consultation; this route typically does not require an NHS referral and offers faster access, though there is a cost. Whichever route you choose, a licensed prescriber will assess your individual health, BMI, and medical history to determine if prescription medication is suitable for you. Both routes offer legitimate, regulated access to these medicines. Speak to your GP about your weight management goals — they can help you understand your options and whether prescription treatment might help alongside dietary changes and increased physical activity.
- 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 warm lemon water actually help you lose weight?
Warm lemon water alone has minimal direct effect on weight loss. While lemon contains vitamin C and some studies suggest citric acid may support digestion, there's no strong evidence that drinking warm lemon water causes fat loss. Weight loss requires a calorie deficit, which is best achieved through sustained dietary changes and physical activity. If you're looking for additional support, prescription medications like Mounjaro and Wegovy have clinical evidence backing their effectiveness.
What is the difference between Mounjaro and Wegovy for weight loss?
Both are prescription-only injections taken once weekly. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro users lost an average of 15–21% body weight, compared to around 15% with Wegovy. Individual results vary, and a prescriber will assess which is most suitable for your health profile.
Am I eligible for prescription weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27 or above with weight-related conditions like type 2 diabetes, high blood pressure, or cardiovascular disease. Lower BMI thresholds may apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. Check your BMI using our free calculator, then speak to your GP or a private prescriber to discuss your individual eligibility.
How can I access weight loss medication on the NHS?
Ask your GP for a referral to your local specialist weight management service (tier 3). You'll undergo an assessment to confirm eligibility and receive prescription and monitoring. Waiting times vary significantly by region. If NHS waiting lists are long, private prescribing is an alternative route available through registered online providers.
How quickly does prescription weight loss medication work?
Weight loss is gradual. Most people see noticeable changes after 4–8 weeks, with significant results over 3–6 months. The medication works best alongside a reduced-calorie diet and increased physical activity. Track your progress with our free progress tracker to monitor changes in weight, BMI, and other metrics over time.
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.