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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Staying on 2.5 mg Mounjaro in the UK
Many people starting Mounjaro remain on the 2.5 mg dose for their weight management journey. This guide covers the cost of staying on this starting dose, how to access it through NHS and private routes in the UK, and what to expect during your treatment. Whether you're exploring options or already prescribed, understanding the financial and practical side of your Mounjaro journey helps you make informed decisions about your health.
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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.
Cost and Access Routes for 2.5 mg Mounjaro in the UK
The cost of staying on 2.5 mg Mounjaro varies significantly between NHS and private prescription routes in the UK. On the NHS, Mounjaro is provided free through specialist tier 3/tier 4 weight management services if you meet eligibility criteria — though waiting lists in many regions can extend several months. Via private prescription, a single 2.5 mg KwikPen (four weekly injections) typically costs between £129 and £180 per month depending on your provider, though prices vary across GPhC-registered online pharmacies. Each pen contains exactly four doses, so monthly costs reflect one pen. The tirzepatide (Mounjaro's active ingredient) itself is the same regardless of provider, but service fees and consultation costs differ. Some private providers include online prescriber consultations in their pricing, whilst others charge separately (typically £15–£50 for a follow-up consultation).
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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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private: How to Access 2.5 mg Mounjaro
NHS route: Your GP can refer you to a specialist weight management service if your BMI is 30 or above, or 27–29.9 with weight-related health conditions. Assessment and prescription happens through the specialist clinic, not your GP. Regional ICBs have different commissioning arrangements, so availability varies widely. Private route: Complete an online health questionnaire with a UK-licensed prescriber (usually within 24 hours). If approved, a prescription is issued and sent to a GPhC-registered pharmacy for dispensing. No NHS referral needed. First consultations may cost more (£50–£100) than follow-ups. Use our GLP-1 weight loss calculator to project potential outcomes at 2.5 mg, helping you decide if this dose suits your goals before committing financially.
- 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 stay on 2.5 mg Mounjaro indefinitely?
Yes, 2.5 mg is a valid maintenance dose for some patients. However, your prescriber may recommend dose escalation if weight loss plateaus or if clinical assessment suggests a higher dose would be beneficial. This is a discussion to have with your healthcare provider — staying on 2.5 mg is medically appropriate if it's supporting your health goals.
What's included in the private prescription cost?
Typically, the cost covers the Mounjaro KwikPen itself, prescriber assessment, and pharmacy dispensing. Some providers include follow-up consultations; others charge separately. Always check what's included before purchasing. Consultation fees are separate from medication costs at some pharmacies.
How long does NHS approval take for Mounjaro 2.5 mg?
NHS waiting times vary by region. Some areas have waiting lists of 3–6 months, whilst others exceed a year. Contact your local ICB or ask your GP about current waiting times in your area. Private prescription is typically faster — usually within 3–5 working days from consultation approval.
Is 2.5 mg Mounjaro cheaper than Wegovy?
Costs are comparable at starter doses. Both Mounjaro 2.5 mg and Wegovy 0.25 mg typically cost £129–£180 per month privately. However, as doses increase, pricing structures differ slightly between providers and medications — compare quotes from GPhC-registered pharmacies for current pricing.
Can my GP prescribe Mounjaro 2.5 mg privately?
No. Private Mounjaro prescriptions must come from a UK-licensed prescriber working through an online consultation service, not from your NHS GP. Your GP can only prescribe Mounjaro if you're referred to an NHS specialist weight management service, which typically prescribes higher doses as part of a supervised programme.
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.