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
What Do GLP-1 Reviews Say About Weight Loss?
GLP-1 medications are prescription-only weight loss injections that have gained significant attention in the UK and globally. Clinical trials and real-world experience show they can help people lose weight when combined with diet and exercise, though individual results vary considerably. This guide looks at what the evidence says, common experiences, and how to access these medications through the NHS or private prescribing. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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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.
What Clinical Evidence Shows About GLP-1 Weight Loss
The most well-known GLP-1 medication for weight management in the UK is Wegovy (semaglutide), which was tested in the STEP clinical trials. The data shows that participants using the maximum 2.4 mg dose lost an average of approximately 15% of their body weight over 68 weeks, alongside a reduced-calorie diet and increased physical activity. Mounjaro (tirzepatide), a newer dual GIP/GLP-1 injection, showed slightly higher results — averaging 15–clinically studied weight loss depending on the dose used in SURMOUNT trials.
- Both medications work by mimicking natural hormones that reduce appetite and support feeling fuller after smaller meals
- Results are individual — some people lose more, some less, and a small proportion may not respond significantly
- Weight loss typically continues for the first 52 weeks, then stabilises while the medication is used
- These are not replacements for lifestyle changes; they work best alongside dietary adjustments and exercise
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.
Real-World Reviews: What Users Report
Feedback from UK users and international reviews consistently highlight similar experiences: appetite reduction is the most reported benefit, with people finding it easier to eat smaller portions. Nausea is very commonly reported in the first 1–2 weeks but often improves as the body adjusts. Many users report increased energy once weight loss begins, and some experience improved blood sugar control. Negative reviews often mention gastrointestinal side effects (nausea, constipation, diarrhoea), injection anxiety, and cost on private prescriptions. Track your progress using our free progress tracker to monitor changes over time.
Importantly, reviews emphasise that GLP-1 medications are not "clinically supported" — they require commitment to healthier eating habits and physical activity. Users who achieve the best results typically combine medication with structured nutrition and exercise plans. Many report that stopping the medication leads to weight regain if lifestyle changes are not maintained, though some find the medication has permanently shifted their relationship with food. NHS weight loss services provide additional support alongside prescription medication, which many users find valuable.
- 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 GLP-1 reviews generally positive or negative?
Clinical trial data is very positive — most participants (70–85%) achieved meaningful weight loss. Real-world reviews are mixed but generally positive about effectiveness; negative reviews usually relate to side effects (especially nausea and gastrointestinal issues) rather than lack of efficacy. Individual experiences vary widely. Use our BMI calculator and weight loss calculator to assess your starting point.
Is Ozempic the same as Wegovy for weight loss?
Both contain semaglutide, but Ozempic is licensed for type 2 diabetes (doses up to 2 mg) and is NOT licensed for weight loss in the UK. Wegovy is the licensed weight management version (up to 2.4 mg). Using Ozempic for weight loss would be off-label prescribing. Always ensure you're prescribed the licensed medication for your condition.
How long do GLP-1 side effects last according to reviews?
Most users report that nausea and stomach discomfort peak in week 1–2, then improve significantly by weeks 3–4. However, some people experience persistent gastrointestinal effects. Reviews suggest that starting at the lowest dose and increasing gradually helps minimise side effects. It's important to discuss this with your prescriber.
Can you stop GLP-1 medication and keep the weight off?
Reviews and clinical data suggest that most people regain weight after stopping GLP-1 medication if lifestyle changes are not sustained. Some users report lasting appetite improvements, but weight regain is common. Long-term medication use is often needed for sustained weight management, which is why combining it with permanent lifestyle changes is crucial.
What's the best way to access GLP-1 medication in the UK?
Two main routes: NHS referral to a tier 3 specialist weight management service (varies by region, can involve waiting lists), or private online prescribing from a UK-licensed prescriber. Private is faster but costs £130–£300+ monthly depending on dose. Your GP can advise on NHS eligibility and local services available 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.