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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Pregabalin and Mounjaro — What's the Difference?
Pregabalin and Mounjaro are two different medicines used in the UK, but they work very differently for weight management. Pregabalin is a nerve pain medication that may have minor effects on appetite, whilst Mounjaro (tirzepatide) is a prescription-only weight management injection specifically designed to help regulate hunger. Understanding how each works, who they're suitable for, and what evidence supports them is important when discussing weight management options with your GP. This guide explains the key differences and how they compare to other weight loss medications like Wegovy.
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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.
How Mounjaro and Pregabalin Work — Mechanism and Purpose
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — a prescription-only injection licensed specifically for weight management in UK adults. It works by activating two natural hormone pathways that help regulate appetite, reduce food cravings, and support feeling fuller after meals. Clinical trials (SURMOUNT-1) showed participants lost an average of 15–21% of body weight when using tirzepatide alongside a reduced-calorie diet and increased physical activity.
Pregabalin is a different medicine entirely — it's a nerve pain medication (also called an anticonvulsant) used to treat conditions like neuropathic pain and anxiety. It is not licensed or approved for weight management in the UK. Whilst some patients report appetite changes as a side effect, weight loss is not its primary purpose and not supported by evidence as a weight management treatment.
- Mounjaro: dual hormone agonist, weight management-specific, once-weekly injection
- Pregabalin: nerve pain medication, not weight-management licensed, taken as tablets
- Different mechanisms, different purposes, different evidence bases
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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.
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Mounjaro vs Wegovy — Weight Loss Medications Compared
If you're exploring weight loss medications, you may also encounter Wegovy (semaglutide), another prescription-only weight management injection licensed in the UK. Both Mounjaro and Wegovy are approved for weight management, but they have different mechanisms. Wegovy is a GLP-1 agonist only, whilst Mounjaro combines GIP and GLP-1 action — the dual mechanism may explain slightly higher average weight loss in SURMOUNT trials versus STEP trials. Both require prescription and clinical assessment. Neither should be confused with pregabalin, which serves a completely different medical purpose. Use our free BMI calculator to check your starting point, and our GLP-1 weight loss calculator to understand potential outcomes with prescription weight loss medications.
- 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.
Is pregabalin ever used for weight loss in the UK?
Pregabalin is not licensed or recommended for weight loss in the UK. While some patients report appetite changes as a side effect, this is not its intended use and weight loss is not supported by evidence. Your GP would not prescribe it for weight management. Mounjaro and Wegovy are the prescription weight loss medications licensed in the UK.
Can I take pregabalin and Mounjaro together?
Both pregabalin and Mounjaro are prescription-only medicines. If you are taking pregabalin for nerve pain and considering Mounjaro for weight management, you must discuss this combination with your GP or prescriber. They will assess whether it's safe and appropriate based on your individual health and current medications.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro participants lost an average of 15–21% body weight, whilst Wegovy participants lost approximately 15%. Both are prescription-only, once-weekly injections. Individual results vary, and suitability depends on your personal health and clinical assessment.
How do I access Mounjaro in the UK?
Mounjaro is available through NHS specialist tier 3 weight management services via GP referral, or through private online prescribing following a clinical assessment. NHS access varies by region and can involve waiting lists. Private prescribers assess your eligibility based on BMI, weight-related health conditions, and medical history. Always use our free BMI calculator to understand your starting point.
What is pregabalin used for if not weight loss?
Pregabalin is licensed in the UK for neuropathic pain (nerve pain), epilepsy, and generalised anxiety disorder. It is not a weight management medication. If you're exploring prescription weight loss options, Mounjaro and Wegovy are the licensed alternatives approved specifically for weight management in UK adults.
Ready to take control of your weight loss journey?
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