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
Free tracker included with every download this week
What To Expect With Mounjaro In The UK
If you're considering Mounjaro (tirzepatide) for weight management in the UK, understanding how to access it and what it costs is essential. Mounjaro is a prescription-only injection available through both NHS specialist services and private online prescribing routes. This guide explains the real costs, eligibility requirements, and what the assessment and prescription process actually involves — so you know what to expect before taking the next 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.
Mounjaro Cost And Access In The UK
NHS access: Mounjaro is approved by NICE for use within NHS specialist weight management services, but access is not straightforward. You'll need referral to a tier 3 or tier 4 specialist weight management service from your GP — standard GPs cannot prescribe it. NHS availability varies significantly by region (ICB), and waiting lists in many areas are substantial, often 6–18 months or longer. When prescribed through the NHS, Mounjaro is free at the point of use (standard prescription charge applies if eligible).
Private access costs: Private prescription routes cost significantly more. A single Mounjaro KwikPen (4-week supply) typically costs £129–£320 per month depending on the dose — lower doses (2.5–5mg) cost less, while higher doses (10–15mg) cost more. Annual private costs can reach £1,500–£3,800. This covers the online clinical assessment, prescription, and medication delivery but does not include GP follow-up or blood tests. Always verify exact pricing with individual providers as costs vary.
- NHS route: Free (or standard prescription charge) but long waits
- Private route: £129–£320 per month depending on dose
- Both routes require clinical assessment before prescription
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 Mounjaro Privately And What The Process Involves
The private online route is faster than NHS referral. You'll complete an online health questionnaire and consultation with a UK-licensed prescriber, who assesses your eligibility based on BMI, health history, and current medications. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy — delivery typically takes 3–7 working days. The Mounjaro KwikPen arrives with clear instructions, and you self-inject once weekly. Some providers offer ongoing prescriber support via messaging or follow-up consultations. Use our free GLP-1 weight loss calculator to estimate potential results, and track your progress with our progress tracker once you've started. Always inform your GP you're taking Mounjaro, even on a private prescription, so they can monitor your health.
- 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 Mounjaro cost per month in the UK?
Private Mounjaro costs £129–£320 per month depending on dose, making annual costs £1,500–£3,800. NHS prescriptions are free (or standard charge) but have significant waiting lists. Prices vary between providers, so compare options before committing.
Can my GP prescribe Mounjaro on the NHS?
No. Standard GPs cannot prescribe Mounjaro. You need referral to a specialist tier 3 or tier 4 weight management service. Ask your GP about referral if you meet eligibility criteria (BMI ≥30 or ≥27 with weight-related health conditions).
How long does the private online assessment take?
Most online assessments take 15–30 minutes to complete. A prescriber reviews your responses within 1–2 working days. If approved, your prescription is issued same day. Medication typically arrives within 3–7 working days.
What's the difference between NHS and private Mounjaro?
The medication is identical. The difference is access speed and cost. NHS is free but involves long waits and specialist referral. Private is faster and immediate but costs £129–£320 monthly. Both require clinical assessment.
What happens if I can't afford private Mounjaro?
Ask your GP about NHS specialist weight management services in your area and request a tier 3 referral. Some areas have faster pathways than others. You can also explore whether lifestyle changes, free NHS resources, or other support might help while on an NHS waiting list.
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.