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 2.5 mg: Starting Dose, Cost & How to Access in the UK
Mounjaro 2.5 mg is the initial starting dose of tirzepatide, prescribed to all patients beginning this GLP-1 and GIP receptor agonist treatment in the UK. This dose is used for the first 4 weeks, after which your healthcare provider may escalate you to 5 mg or higher depending on your response. The cost and access route for Mounjaro varies significantly depending on whether you pursue NHS funding through specialist weight management services or opt for private prescription through UK-licensed online providers. Understanding your options, eligibility criteria, and realistic timelines is essential before starting treatment.
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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 2.5 mg Cost in the UK: Private vs NHS Routes
Private prescription costs: Mounjaro 2.5 mg through private online prescribing typically costs between £129 and £200 per month, depending on the provider and whether additional follow-up consultations are included. Each KwikPen contains 4 weekly doses (a 4-week supply), so you'll need one pen per month at the starting dose. Costs may vary slightly between GPhC-registered pharmacies.
NHS access: If available through your local NHS integrated care board (ICB), Mounjaro is typically free at point of care following assessment by a tier 3 specialist weight management service. However, NHS access is extremely limited in many regions, with significant waiting lists (sometimes 12–24 months). Your GP can refer you to your local specialist service, though referral acceptance depends on local commissioning decisions and availability.
Dose escalation costs: Private costs remain similar as you escalate from 2.5 mg to higher doses (5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg), as each dose uses one KwikPen per 4 weeks.
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 vs Private: How to Access Mounjaro 2.5 mg Starting Treatment
NHS route: Ask your GP for a referral to your regional tier 3 weight management service. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, sleep apnoea, etc.). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds. Be prepared for waiting lists and regional variation in availability and funding decisions.
Private online prescription route: Consult with a UK-licensed prescriber through a GPhC-registered pharmacy. The process typically takes 1–3 days: complete an online health questionnaire, have a brief video or phone consultation, receive a prescription if clinically appropriate, and have your first KwikPen dispensed. No GP referral needed. Use our GLP-1 weight loss calculator to estimate your potential results and help inform your decision.
- 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.
Is Mounjaro 2.5 mg the dose I'll stay on?
No. 2.5 mg is the starting dose only, used for the first 4 weeks to allow your body to adjust. Your healthcare provider will typically increase your dose every 4 weeks (following a dose titration schedule) until reaching a maintenance dose, usually 10 mg or 15 mg. Escalation depends on your tolerance and response. Always follow your prescriber's guidance on timing.
How much does a month's supply of Mounjaro 2.5 mg cost privately in the UK?
Private prescription costs typically range from £129 to £200 per month for Mounjaro 2.5 mg through UK online pharmacies. Costs may vary slightly between providers and may include or exclude follow-up consultation fees. Prices are often similar across different doses as each uses one KwikPen monthly.
Can I get Mounjaro 2.5 mg on the NHS?
Potentially, but NHS access is extremely limited and varies by region. Your GP can refer you to a specialist tier 3 weight management service if you meet eligibility criteria (BMI ≥30, or ≥27 with comorbidities). However, many areas have very long waiting lists, and some ICBs do not currently commission tirzepatide. Ask your GP about your local service availability.
What happens after 4 weeks on Mounjaro 2.5 mg?
After your first 4 weeks on 2.5 mg, your prescriber will review your response and tolerability. If you're tolerating the medication well, your dose will typically escalate to 5 mg for weeks 5–8. This gradual dose titration continues every 4 weeks until you reach an effective maintenance dose, usually 10–15 mg.
How do I check if I'm eligible for Mounjaro on the NHS?
Contact your GP and ask for a referral to your local tier 3 specialist weight management service. Eligibility criteria include: BMI 30 or above, or BMI 27–29.9 with at least one weight-related health condition (diabetes, hypertension, sleep apnoea). South Asian and Black heritage adults may have lower thresholds. Your GP can advise on local commissioning and waiting times. Use our BMI calculator above to check your personal BMI as a first step.
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.