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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Running Weight Loss: UK Prescription Medication Guide
If you're looking to lose weight through running combined with professional support, prescription weight loss medication may be an option. The UK has several NHS and privately-available medications approved for weight management. This guide explains what's available, who's eligible, and how to access treatment. Whether you're considering medication alongside exercise or exploring all your options, understanding what prescription weight loss the NHS and private providers offer is an important first step.
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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 Management Medications
Three prescription-only medications are currently licensed in the UK for weight management in adults:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks, alongside reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Clinical evidence demonstrated approximately 15% average weight loss in trials, with results varying between individuals.
- Saxenda (liraglutide) — a daily GLP-1 injection option, approved for longer-term use.
All three work by helping reduce appetite, increase feelings of fullness, and support sustainable weight loss when combined with lifestyle changes including regular exercise like running. Each requires a clinical assessment before prescription. Use our free GLP-1 weight loss calculator to explore 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 Weight Loss Medication
In the UK, weight loss medication can be accessed through both NHS specialist services and private online prescribing. NHS access requires referral to a tier 3 specialist weight management service through your GP — availability and waiting times vary significantly by region. Private access involves an online consultation with a UK-licensed prescriber followed by dispensing through a GPhC-registered pharmacy, without requiring NHS referral.
To find out if you're eligible, speak with your GP about your weight management goals and health history. Eligibility typically requires 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. Use our free BMI calculator to check your current BMI and understand your starting point.
Whether you're combining prescription medication with running or exploring weight management options, a conversation with your GP is the best starting point. They can assess your individual health, discuss whether nhs weight loss medication or private options are suitable for you, and help you understand realistic timescales and outcomes. Individual results vary — some people respond very well while others may need dose adjustments or alternative approaches. Sustainable weight loss combines medication (if appropriate) with consistent running, balanced nutrition, and lifestyle changes. Track your progress using our free progress tracker to monitor results over weeks and months.
- 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.
Can I take weight loss medication while running?
Yes. Prescription weight loss medications like Mounjaro and Wegovy are designed to be used alongside lifestyle changes including regular exercise. Running complements medication by improving cardiovascular health, supporting calorie deficit, and enhancing overall weight loss outcomes. Always discuss your exercise routine with your prescriber, as some people initially experience reduced energy while adjusting to medication.
How long does it take to see weight loss results with medication?
Most people begin noticing weight loss within 2–4 weeks of starting medication, though some take longer. Clinical trials typically assessed results over 12–16 weeks to account for individual variation. Sustained weight loss usually continues for 6–12 months, depending on dose and individual response. Results vary significantly between people.
What's the difference between GLP-1 and Mounjaro?
GLP-1 medications (like Wegovy and Saxenda) work through one hormone pathway. Mounjaro is a dual GIP and GLP-1 agonist, activating two pathways simultaneously, which may offer slightly greater average weight loss in clinical trials. Both require prescription and clinical assessment. The best choice depends on individual health factors and prescriber recommendation.
Do I need a GP referral for private weight loss medication?
No. Private prescription weight loss medication in the UK does not require NHS referral. You can contact a private online prescriber directly for a consultation. However, informing your GP that you're considering or using prescription weight loss medication is recommended for coordinated care, especially if you have other health conditions or take other medications.
What happens if weight loss medication doesn't work for me?
Individual responses vary — some people lose significant weight while others lose more modest amounts. If initial medication isn't effective, your prescriber may adjust the dose, switch to a different medication, or discuss alternative approaches. Combining medication with consistent running, reduced-calorie diet, and behaviour changes offers the best outcomes. Your GP or prescriber can guide next steps based on your progress.
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.