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 for Men in the UK — Prescription Medication Options
Many men in the UK are exploring prescription weight management options to support sustainable weight loss alongside lifestyle changes. If you're considering weight management, it's important to understand what prescription medications are available, who is eligible, and how to access them through either the NHS or private prescribing. This guide covers the evidence-based weight loss medications licensed in the UK and how to find out if you're eligible for treatment.
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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 Medications
Three prescription weight management medications are currently licensed in the UK for adults with excess weight:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 hormone pathways. Clinical trials showed men lost an average of 15–21% of their body weight over 72 weeks, though individual results vary.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Evidence from clinical trials demonstrated average weight loss of approximately 15% body weight, with results most significant when combined with reduced-calorie diet and increased physical activity.
- Saxenda (liraglutide) — a daily GLP-1 injection, the longest-established weight loss medication in the UK.
All three require a prescription following clinical assessment. Eligibility typically requires a BMI of 30 kg/m² or above, or 27 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Use our free BMI calculator above to check your personal BMI and understand where you fall within NHS weight categories.
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.
How to Access Weight Loss Medication in the UK
There are two main routes to access prescription weight loss medication in the UK. The NHS route involves referral to a specialist tier 3 weight management service through your GP — availability and waiting times vary significantly by region. The private route involves consultation with a UK-licensed prescriber through an online pharmacy, available without NHS referral.
Your GP can discuss which option suits your circumstances and assess your eligibility. Before any appointment, calculate your BMI using our free BMI calculator on this page, and track your current weight using our progress tracker to show your starting point. Having this information ready helps your healthcare professional assess whether prescription medication is appropriate for you.
- 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 can men typically lose with prescription medication?
In clinical trials, men using Mounjaro lost an average of 15–21% of their body weight, while Wegovy users lost approximately 15%. However, individual results vary significantly and depend on adherence, diet, physical activity, and personal metabolism. Results are most effective when medication is combined with sustained lifestyle changes.
What are the main side effects of weight loss injections?
Common side effects include nausea, diarrhoea, constipation, and stomach discomfort—these often reduce after the first few weeks. Less common side effects include fatigue, dizziness, and injection site reactions. Serious side effects are rare but include severe stomach pain (possible pancreatitis) and allergic reactions. Always discuss potential side effects with your prescriber.
Am I eligible for weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 kg/m² or above, or 27 kg/m² with weight-related health conditions. However, availability varies by region and waiting lists can be lengthy. Your GP can refer you to a specialist weight management service for assessment, or you can explore private prescribing options without waiting for an NHS referral.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections, but Mounjaro works on two hormone pathways (GIP and GLP-1) while Wegovy targets GLP-1 only. Clinical data suggests Mounjaro may produce slightly higher average weight loss, but individual results vary. Your prescriber will help determine which is most appropriate for your circumstances.
How does weight loss medication work alongside lifestyle changes?
Prescription weight loss injections are designed to support—not replace—diet and exercise. They work by reducing appetite, helping you feel fuller after smaller meals, and supporting better food choices. Combined with a reduced-calorie diet and increased physical activity, evidence shows these medications help men achieve more sustainable weight loss than lifestyle changes alone. ```
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.