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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Weight Loss Tea vs Prescription Medication in the UK
While weight loss and detox teas are popular, they contain minimal active ingredients and lack clinical evidence for significant weight loss. If you're looking for proven weight management solutions in the UK, prescription medications are available for eligible adults. This guide explains UK-licensed options, how they work, and whether you might qualify for prescription weight loss medication on the NHS or privately.
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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 seeking effective weight management in the UK, three prescription medications are licensed for weight loss: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 receptor agonist medications that work by reducing appetite and helping you feel fuller after smaller meals.
- Mounjaro: Dual GIP and GLP-1 agonist, once-weekly injection, average weight loss 15–21% of body weight in clinical trials
- Wegovy: GLP-1 agonist, once-weekly injection, average weight loss around 15% in clinical trials
- Saxenda: GLP-1 agonist, daily injection, slightly lower average weight loss but also effective
Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Results vary significantly between individuals, and these medications work best alongside a reduced-calorie diet and physical activity. Calculate your personal BMI using our free tool to check where you stand, and try our GLP-1 weight loss calculator to estimate 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.
NHS Access vs Private Prescription in the UK
NHS route: GPs can refer you to specialist tier 3 weight management services where prescription weight loss medication may be prescribed. Access varies significantly by region, and waiting lists can be lengthy in many areas. Your GP can assess your eligibility and discuss whether specialist referral is appropriate.
Private route: You can access prescription weight loss medication through a UK-licensed online prescriber and GPhC-registered pharmacy without NHS referral. A clinical assessment is still required — a prescriber will review your health to ensure the medication is safe for you. Costs typically range from £129–£320 per month depending on dose. Whether you choose NHS or private, prescription weight loss medication offers proven clinical results — far more effective than any tea-based supplement.
The first step is to understand your current BMI and health context. Use our free BMI calculator above to check your personal BMI against NHS guidelines. If you fall within the eligible range, start a conversation with your GP about weight management options. Your GP can refer you to NHS specialist services or discuss whether private prescription options suit your circumstances. Keep in mind that prescription medications work best alongside lifestyle changes — diet, physical activity, and behavioural support all matter. If you're tracking progress, our free progress tracker helps you log weight, measurements, and milestones over time.
- 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.
Are weight loss and detox teas effective for weight loss?
Most commercially available weight loss and detox teas lack robust clinical evidence for significant weight loss. They may contain caffeine or mild diuretics, which can cause temporary water weight loss, but don't address the underlying biology of appetite and calorie balance. Prescription GLP-1 medications have strong clinical trial data supporting 15–21% average weight loss.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections, but Mounjaro is a dual GIP and GLP-1 agonist while Wegovy is GLP-1 only. In clinical trials, Mounjaro showed slightly higher average weight loss (15–21%) compared to Wegovy (around 15%). Eligibility and side effects are similar, and a prescriber can help determine which suits your individual circumstances.
Can I get prescription weight loss medication on the NHS?
Yes, GPs can refer you to specialist tier 3 weight management services where prescription medications may be offered. Eligibility criteria include a BMI of 30 or above, or 27–29.9 with weight-related health conditions. NHS availability and waiting times vary significantly by region — your GP can advise on local services.
How do I know if I'm eligible for prescription weight loss medication?
Eligibility is based on BMI and health conditions. Calculate your BMI using our free calculator above to see where you stand. Adults with a BMI of 30 or above, or 27–29.9 with conditions like type 2 diabetes or high blood pressure, may qualify. A prescriber will assess your full health history to confirm suitability.
What's the average weight loss with prescription medications like Mounjaro?
In clinical trials, Mounjaro achieved average weight loss of 15–21% of body weight over 72 weeks alongside reduced-calorie diet and physical activity. However, individual results vary significantly — some people lose more, others less. A prescriber can discuss realistic expectations based on your personal health and lifestyle factors.
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.