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 Mounjaro 2.5mg in the UK
Some people find that staying on the Mounjaro 2.5mg starting dose provides the weight loss results they need without escalating further. This guide explains how to access and maintain the 2.5mg dose in the UK, including costs on the NHS and through private prescription routes. Individual responses to tirzepatide vary — some patients achieve meaningful weight loss at lower doses, while others require escalation. Your prescriber will assess what works best for your health goals and circumstances.
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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.
Mounjaro 2.5mg Cost in the UK
The cost of Mounjaro in the UK varies significantly between the NHS and private routes. On the NHS, Mounjaro is available through specialist tier 3 weight management services, but access is limited and varies by region — many areas have long waiting lists or restricted eligibility criteria. The NHS does not separately charge patients for the medication itself once prescribed through a specialist service.
Through private prescription, Mounjaro 2.5mg typically costs between £129 and £199 per month depending on the provider and whether you're accessing a first dose or a repeat supply. Each Mounjaro KwikPen contains 4 doses, so one pen lasts 4 weeks at the 2.5mg maintenance dose. Costs may vary slightly based on consultation fees and delivery charges. Many online prescription services offer subscription models that can reduce per-dose costs if you commit to ongoing treatment. Always compare providers, as pricing can vary considerably across UK-registered online pharmacies.
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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 Access for Mounjaro 2.5mg
NHS route: Request a referral to your local tier 3 specialist weight management service through your GP. Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Availability and waiting times vary significantly by region — some areas have 6–12 month waits. Once assessed and approved, the medication is provided free, though you'll need to attend regular monitoring appointments.
Private route: Complete an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy. Assessment usually takes 24–48 hours. If approved, a prescription is issued and the medication is posted to your address. You can continue on 2.5mg indefinitely if it suits your goals, though most prescribers recommend regular check-ins. Use our free GLP-1 weight loss calculator above to estimate potential outcomes at different doses, and track your progress with our progress tracker.
- 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 Mounjaro 2.5mg indefinitely?
Yes, if your prescriber approves and the dose is supporting your weight loss goals. However, most clinical guidance suggests staying on any dose for a minimum of 4 weeks before assessing whether to continue or escalate. Your prescriber may recommend periodic review appointments to ensure the medication remains appropriate for your health.
Is Mounjaro 2.5mg as effective as higher doses?
Clinical trial data shows that effectiveness increases with dose — the 15mg dose produced greater average weight loss than 2.5mg. However, individual responses vary considerably. Some people achieve their weight loss goals at 2.5mg, especially when combined with diet and exercise. Your GP or prescriber can discuss whether this dose is suitable for your specific situation.
How long does a Mounjaro 2.5mg pen last?
Each KwikPen contains 4 pre-filled doses. At 2.5mg once weekly, one pen lasts exactly 4 weeks. You'll need a new pen every month if staying on this dose. Private providers typically deliver on a monthly subscription basis to ensure continuity.
Will the NHS prescribe Mounjaro 2.5mg if I don't escalate?
The NHS can prescribe Mounjaro at any approved dose, including 2.5mg, if it aligns with your treatment plan. However, NHS services typically follow dose escalation protocols — staying at the starting dose indefinitely would be unusual but not impossible if clinically justified. Discuss this with your specialist weight management service.
What if private Mounjaro is too expensive on 2.5mg?
Compare costs across different UK online prescription providers, as pricing varies. Some services offer discounted rates for subscription models. Alternatively, discuss NHS referral options with your GP — though waiting lists can be lengthy in many areas. Our BMI calculator can help you understand your eligibility for NHS services.
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.