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
GLP-1 Weight Loss Reviews — Evidence and Real-World Outcomes
GLP-1 medications like Wegovy and Mounjaro have generated significant interest as prescription weight loss treatments in the UK. Rather than focusing on individual reviews, this guide explains what clinical evidence actually shows about how these medications work, their typical results, and whether they might be suitable for you. Understanding the science behind GLP-1 weight loss helps you make informed conversations with your GP or healthcare provider about prescription weight loss options.
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.
What Clinical Trials Show About GLP-1 Weight Loss
Clinical trial data provides the most reliable evidence for GLP-1 effectiveness. Wegovy (semaglutide) was tested in the STEP trials, showing participants lost an average of approximately 15% of their body weight over 68 weeks when combined with a reduced-calorie diet and increased physical activity. Mounjaro (tirzepatide) demonstrated even greater average weight loss—around 15–21% depending on dose—in the SURMOUNT trials using the same lifestyle approach.
These results represent averages; individual outcomes vary considerably. Some people lose significantly more weight, while others see more modest results. Weight loss typically occurs gradually over weeks and months, not immediately. Both medications work by activating GLP-1 pathways in the brain that regulate appetite, reduce cravings, and promote feelings of fullness. For weight management in the UK, these medications are prescription-only and require clinical assessment before prescribing to ensure they are appropriate for your individual health profile.
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 Experience vs. Clinical Data
While clinical trials provide objective evidence, real-world experiences reported online may not reflect the full picture. Individual responses to GLP-1 treatment depend on genetics, lifestyle adherence, starting weight, and how your body responds to the medication. Some users report feeling less hungry and more satisfied with smaller portions; others find side effects like nausea challenging in the first few weeks. The NHS weight loss approach emphasizes combining medication with dietary changes and physical activity for best results.
Remember that online reviews may be skewed—people with extreme results (very successful or disappointed) are more likely to post than those with average outcomes. Your own experience may differ from what you read. Our free GLP-1 weight loss calculator can help you explore potential results based on clinical data, and speaking with your GP ensures any treatment plan is tailored to your specific circumstances and health goals.
- 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.
How much weight do people typically lose on GLP-1 medication?
Clinical trials show average weight loss of 15–21% of body weight over 68 weeks with Wegovy or Mounjaro, alongside diet and exercise. However, individual results vary significantly—some lose more, others less. Results depend on genetics, lifestyle changes, starting weight, and personal response to the medication. Always use conditional language: these medications may help, but outcomes are not assured.
How quickly do GLP-1 injections work for weight loss?
Weight loss typically begins within weeks but becomes more noticeable over months. Both Wegovy and Mounjaro require gradual dose escalation—starting low and increasing weekly until reaching maintenance dose. Most people reach their plateau weight loss around 16–20 weeks. Patience is essential; GLP-1 is not a rapid-action treatment but supports sustainable, long-term weight management in the UK.
Are GLP-1 reviews on social media reliable for predicting my results?
Social media reviews may not be representative. People with extreme outcomes are more likely to post, creating selection bias. Additionally, individual responses vary based on genetics, adherence to lifestyle changes, and personal health factors. Clinical trial data is more objective. Use our free BMI calculator to understand your starting point, then discuss realistic expectations with your GP.
What's the difference between Wegovy and Mounjaro in reviews?
Both are prescription-only GLP-1 medications licensed for UK weight loss. Wegovy (semaglutide) activates the GLP-1 pathway; Mounjaro (tirzepatide) activates both GLP-1 and GIP pathways. Clinical trials show similar average weight loss, though Mounjaro may produce slightly higher averages. Choice depends on individual suitability, assessed by your prescriber during clinical assessment.
Can I trust weight loss reviews if I have a BMI in the overweight range?
Reviews from people at different starting weights may not predict your results. Someone starting at BMI 35 may lose more total kilograms than someone starting at BMI 27. Your baseline BMI, health conditions, diet, and exercise adherence all influence outcomes. Check your BMI using our free BMI calculator, then discuss personalised expectations with your healthcare provider regarding prescription weight loss options.
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.