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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Mounjaro Monthly Subscription: UK Prescription Guide
Mounjaro is not typically available as a traditional "monthly subscription" in the UK — instead, you receive a prescription for a one-month supply (4 weekly injections in a KwikPen box) that you repeat monthly if continuing treatment. Access is through either NHS specialist weight management services or private online prescribers following a clinical assessment. Understanding how Mounjaro prescribing works helps you plan treatment access and costs. This guide explains UK prescription options, what's included each month, and how to access tirzepatide (the active ingredient in Mounjaro) through legitimate healthcare channels.
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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 Prescriptions Work in the UK
Mounjaro is a prescription-only weight management injection containing tirzepatide. In the UK, prescriptions are issued monthly rather than as ongoing "subscriptions" — each prescription covers a 4-week supply of one dose strength.
What you receive each month:
- One KwikPen box containing 4 pre-filled injection pens
- Each pen delivers your prescribed dose once weekly
- Storage instructions: refrigerate unopened pens at 2–8°C; can be kept at room temperature for up to 30 days after first use
- Prescription valid for one month; you'll need a repeat prescription for ongoing treatment
If you're dose titrating (increasing gradually from 2.5mg up to 15mg), your prescription dose will change every 4 weeks. You cannot order multiple months at once — each month requires a new prescription. This ensures your prescriber reviews your progress and tolerability regularly.
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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.
Free Weight Loss Tools & Guides
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NHS vs Private Access to Monthly Mounjaro
NHS access: Available through specialist tier 3 weight management services following GP referral. Costs are covered by the NHS, but waiting lists vary by region and can be lengthy (sometimes months to years). NICE has approved tirzepatide for NHS use, but availability depends on your local integrated care board (ICB).
Private access: Available through GPhC-registered online pharmacies. You pay per prescription (costs typically £129–£320 monthly depending on dose). Private prescriptions are issued by UK-licensed prescribers following an online clinical assessment. No NHS referral needed. You can order monthly repeats, though each repeat requires prescriber approval. Use our GLP-1 weight loss calculator to understand potential outcomes at different doses, and our BMI calculator to check your eligibility based on current health status.
What "monthly subscription" really means: Unlike subscription services, Mounjaro operates on a per-prescription basis. You don't sign a contract or pay a fixed annual fee. Instead, you arrange a prescription each month—either through NHS services or by contacting a private prescriber for a repeat. Some private providers offer automated repeat ordering, where your prescription is renewed monthly unless you cancel. This is closer to a subscription model, but it's technically monthly prescription repeats, not a formal subscription product. Always check with your prescriber about their repeat ordering process and cancellation policy.
- 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 does a month of Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129 to £320 per month depending on your dose. Lower doses (2.5–5mg) are usually cheaper; higher doses (10–15mg) cost more. Prices vary between providers. Cost includes the prescription and the monthly KwikPen box. Always confirm the exact price with your chosen prescriber before starting treatment.
Can I get Mounjaro on the NHS as a monthly prescription?
Yes, Mounjaro is available through NHS specialist weight management services (tier 3). You'll need a GP referral. Costs are covered by the NHS, but regional availability varies significantly. Some areas have long waiting lists. Contact your local integrated care board or ask your GP about NHS weight management services in your area.
What happens if I want to stop taking Mounjaro after a month?
You can stop at any time—simply don't request a repeat prescription. There's no cancellation fee or contract. However, stopping suddenly may cause appetite to return quickly. Discuss the best way to stop with your prescriber. You may want to taper off gradually or discuss alternative strategies.
Do I need a new prescription each month or can I get multiple months at once?
In the UK, prescriptions are typically issued monthly. You cannot usually get multiple months' supply in one prescription. Each month requires a fresh prescription, allowing your prescriber to review your progress and tolerability. Some private providers offer automated monthly renewal systems for convenience.
Is Mounjaro the same as Ozempic, and can I get either on monthly prescription?
Both contain semaglutide, but Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist licensed for weight management. Ozempic is a GLP-1-only medication licensed for type 2 diabetes—it's not officially approved for weight loss in the UK. For weight management, Wegovy (also semaglutide) is the licensed option alongside Mounjaro. Ask your prescriber which is appropriate for you.
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