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 Medication Reviews in the UK
If you're researching weight loss medication reviews in the UK, you'll find that prescription weight management options are now available to eligible adults. This guide covers the licensed medications approved by UK health authorities, how they work, what clinical evidence shows, and how to find out if you qualify. Whether you're exploring NHS weight loss pathways or private options, understanding the facts about these treatments can help you make an informed decision with your GP.
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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 Weight Loss Medications
Three prescription weight loss medications are currently licensed in the UK for weight management in adults:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist administered once weekly. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a GLP-1 receptor agonist given as a once-weekly injection. Trial data demonstrated average weight loss of approximately 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — a GLP-1 agonist administered as a daily injection, with average weight loss around 5–10% of body weight in clinical studies.
All three require a prescription following clinical assessment and are used alongside lifestyle changes, not as standalone treatments. Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses for weight management UK contexts.
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.
Eligibility and How to Access Treatment
To access prescription weight loss medication in the UK, you must meet specific eligibility criteria. Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea, may qualify. Use our free BMI calculator to check your personal BMI, then discuss your results with your GP.
You can access these medications through two routes: NHS specialist services — typically via tier 3 weight management services with potential waiting lists — or private prescribing through registered online services following an online clinical assessment. Your GP can advise on NHS availability in your area and help you explore the best route for your circumstances.
- 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.
Which weight loss injection is most effective according to reviews?
Clinical trial data shows Mounjaro (tirzepatide) achieved slightly higher average weight loss (15–21%) compared to Wegovy (semaglutide) at approximately 15%. However, individual results vary significantly. Effectiveness depends on your personal health, dose achieved, and adherence to dietary and exercise changes. Your GP can discuss which medication suits your circumstances best.
Can I get weight loss medication on the NHS in the UK?
Yes. NHS England has approved prescription weight loss medications including tirzepatide (Mounjaro) for eligible adults through specialist tier 3 weight management services. However, availability and waiting times vary significantly by region and integrated care board. Contact your GP to ask about NHS services in your area and whether you meet eligibility criteria.
How much do weight loss injections cost privately in the UK?
Private costs for GLP-1 and GIP/GLP-1 medications range from approximately £129–£320 per month depending on the medication, dose, and provider. Prices vary between registered online pharmacies. You'll need a prescription from a UK-licensed prescriber, which usually requires an online clinical consultation fee (typically £30–£50). Compare providers for current pricing.
Are weight loss medication reviews reliable for making a decision?
Online reviews can offer personal perspectives but shouldn't be your only source. Clinical trial data and NHS guidance provide more objective evidence. Reviews reflect individual experiences and results vary widely based on genetics, lifestyle, and personal health factors. Always discuss weight loss medication with your GP or a licensed prescriber to understand whether it's appropriate for you personally.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro is a dual GIP and GLP-1 receptor agonist; Wegovy is GLP-1 only. Mounjaro clinical trials showed slightly higher average weight loss. Both are once-weekly injections licensed in the UK. Wegovy has been available longer. Your prescriber will assess which suits your health profile better. Both require prescription and clinical assessment — results and side effects vary individually.
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.