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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What People Say About Mounjaro in the UK
Mounjaro (tirzepatide) has become increasingly discussed in the UK for weight management, but understanding real-world access and costs is essential before considering it. This guide explains how Mounjaro works in UK practice, what it actually costs through private prescription, how NHS access compares, and what people consistently report about their experience. Whether you're exploring NHS routes or considering private prescription through an online consultation, knowing the practical reality helps you make an informed decision.
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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 Private Access and Real Costs
In the UK, Mounjaro is available through private prescription without NHS referral, dispensed by GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Private costs typically range from £129 to £320 per month depending on your dose — higher doses cost more because each KwikPen contains 4 weeks of injections at a fixed dose.
- 2.5 mg starting dose: approximately £129–£160/month
- 5–7.5 mg maintenance: approximately £180–£220/month
- 10–15 mg higher doses: approximately £240–£320/month
These costs are approximate and vary between providers. Most people start at 2.5 mg for 4 weeks, then increase weekly, so initial costs are lower. Users commonly report that costs become steady once they reach their maintenance dose. What people consistently mention in reviews is that private access is significantly faster than NHS waiting lists — prescriptions can typically be issued within days of assessment, not months.
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 Versus Private Routes
NHS access to tirzepatide (Mounjaro) exists but is limited. NICE has approved tirzepatide for specialist weight management services, but availability depends on your regional Integrated Care Board. NHS prescriptions come through tier 3 specialist weight management services, not standard GPs. Waiting lists in many areas are extremely long — often 12+ months. People reviewing their experience consistently note that NHS access requires meeting strict BMI thresholds and having documented weight management attempts first.
Private prescription is faster: Online consultations typically take 24–48 hours, assessment is straightforward if you meet eligibility criteria (BMI ≥27 with health conditions, or ≥30), and prescriptions are issued promptly. You'll need a genuine clinical assessment — prescribers will ask about your medical history, current medications, and weight loss goals. Use our BMI calculator above to check where you stand against eligibility criteria before contacting a prescriber.
- 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.
What dose of Mounjaro do most UK users start on?
The standard starting dose is 2.5 mg once weekly for 4 weeks. After 4 weeks, most people increase to 5 mg for the next 4 weeks. Doses continue increasing weekly by 2.5–5 mg increments until reaching a maintenance dose, typically 10–15 mg. Each person's titration schedule depends on how well they tolerate the injection and their response.
Is Mounjaro available on the NHS in the UK?
Yes, but access is very limited and varies by region. NICE has approved tirzepatide for specialist NHS weight management services (tier 3), but you need referral from your GP and typically face long waiting lists. Private prescription is significantly faster — usually within days rather than months — and doesn't require NHS referral.
How long does a Mounjaro KwikPen last?
Each pre-filled KwikPen contains 4 doses, so one pen lasts exactly 4 weeks. When your KwikPen is empty, you order your next pen at the same dose (or at an increased dose if your prescriber recommends a titration step). This means you'll need a new prescription roughly every 4 weeks if you're increasing dose, or ongoing prescriptions if you're on a stable maintenance dose.
Can I switch from Wegovy to Mounjaro through the NHS?
Not typically. Both are available through NHS specialist services, but access to either depends on your regional ICB commissioning. If you're already on Wegovy through NHS, switching to Mounjaro would need prescriber approval and likely requires going through your specialist service again. Private providers can assess switching, but it's not an automatic process.
What's the difference between reading Mounjaro reviews online and getting a real assessment?
Online reviews give you a sense of common experiences — side effects, weight loss timelines, cost feedback — but they're not personalised. A clinical assessment with a prescriber is essential because they evaluate your individual health, medications, and suitability. Review experiences are helpful context, but your own assessment determines whether Mounjaro is appropriate for you specifically.
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.