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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Is 2.5mg Mounjaro Effective for Weight Loss in the UK?
The 2.5mg dose of Mounjaro is the starting dose used when first beginning treatment with tirzepatide in the UK. While it's not the maximum effective dose, clinical evidence suggests that even at this level, patients may experience weight loss when combined with a reduced-calorie diet and increased physical activity. Whether 2.5mg is effective for you personally depends on your individual response, starting weight, and how long you remain on this dose — most patients increase their dose every 4 weeks. Understanding the cost and access routes in the UK helps you make an informed decision about whether this prescription injection is right for your situation.
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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.
What Does Mounjaro 2.5mg Cost in the UK?
Private prescription costs for Mounjaro 2.5mg vary depending on the provider, but typically range from approximately £130 to £180 per KwikPen (a 4-week supply). This makes monthly costs roughly £130–£180 when paying privately. The 2.5mg dose is the starting point in the Mounjaro dose titration schedule — most patients progress to 5mg after 4 weeks, then increase further if needed, which can affect ongoing costs.
- Costs vary between online prescription providers in the UK
- Each KwikPen contains 4 weekly injections (one month's supply)
- You'll need a clinical assessment before a prescription is issued
- Prices may change and you should compare current quotes from GPhC-registered pharmacies
- Private costs are not covered by NHS prescriptions
In comparison to Wegovy (semaglutide), Mounjaro often has different pricing at equivalent dose levels, though direct cost comparisons depend on your specific provider. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses to help guide your decision.
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 Access — How to Get Mounjaro 2.5mg in the UK
NHS access: Mounjaro (tirzepatide) is approved by NICE for use within specialist NHS weight management services. However, access is limited to tier 3/4 specialist services, typically requiring a GP referral. Waiting times can be several months or longer depending on your local ICB (Integrated Care Board). Not all areas have equal provision.
Private access: You can obtain a Mounjaro prescription privately through a GPhC-registered online prescriber following an online clinical consultation. This typically takes 24–48 hours and doesn't require an NHS referral. Once approved, your prescription is dispensed by a registered pharmacy. The online consultation assesses your BMI, health history, and eligibility — prescription is only issued if clinically appropriate. Use our free BMI calculator above to check your starting point before consultation.
- 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 2.5mg Mounjaro an effective starting dose?
2.5mg is the starting dose for all patients in the UK — it's not the maximum effective dose. Clinical trials showed that higher doses (5mg, 10mg, 15mg) produced greater average weight loss than 2.5mg alone. However, starting low allows your body to adjust and helps the prescriber assess tolerability before increasing. Most patients increase to 5mg after 4 weeks.
How much weight can you lose on 2.5mg Mounjaro?
Individual results vary significantly. In clinical trials (SURMOUNT-1), participants on tirzepatide achieved greater weight loss at higher doses than at 2.5mg. Since 2.5mg is a starting dose, most patients stay on it for only 4 weeks before increasing. Weight loss depends on diet, exercise, individual metabolism, and how long you remain on each dose. Results are not assured.
How long do you stay on 2.5mg Mounjaro?
The standard dose titration schedule recommends staying on 2.5mg for weeks 1–4 only. After 4 weeks, if tolerated well, most patients increase to 5mg. Dose increases continue every 4 weeks until reaching an effective maintenance dose or the maximum of 15mg. Your prescriber determines the pace based on your response and side effects.
Can I get Mounjaro on the NHS in the UK at 2.5mg?
Yes, Mounjaro is available through NHS specialist weight management services (tier 3/4), but access varies significantly by region. Waiting times are often long. You would start at 2.5mg and increase according to the dose titration schedule. Private access is faster — prescription issued within 24–48 hours after an online clinical assessment with a UK-licensed prescriber.
What's the difference between NHS and private Mounjaro access?
NHS access requires a GP referral to specialist services and can involve long waiting lists; costs are covered by the NHS. Private access is faster (24–48 hours) and doesn't require an NHS referral, but you pay privately (approximately £130–£180 per KwikPen). Both require clinical assessment to confirm eligibility. Your GP can advise which route is best for your situation.
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.