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 Bruising — What It Means for Cost and Access
Bruising at the injection site is one of the most common side effects of Mounjaro (tirzepatide), affecting many people starting this prescription weight management injection. This guide explains why bruising happens, how to minimise it, and crucially — how it affects your ability to access Mounjaro in the UK and what you'll pay. Whether you're considering NHS or private routes, understanding injection site reactions helps you make an informed decision.
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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.
How Mounjaro Bruising Affects Access and Cost in the UK
Bruising at the Mounjaro KwikPen injection site is a common but not serious side effect — it affects up to 1 in 10 people. The good news: injection site bruising alone will not prevent you from continuing Mounjaro, and it does not increase the cost of your prescription. Bruising typically fades within 7–14 days and becomes less common as your skin adjusts to regular injections.
Cost implications are minimal: Whether you develop bruising or not, your Mounjaro prescription cost remains the same — around £129 to £320 per month depending on your dose (starting at 2.5 mg, up to maximum 15 mg). NHS prescriptions cost £9.90 per item if you're not exempt. Private prescription costs are set by your online prescriber and dispensing pharmacy, not by side effects.
- Bruising does not affect NHS eligibility or specialist assessment
- It does not change private prescription costs
- Rotating injection sites (stomach, thigh, upper arm) helps reduce bruising
- Allowing skin to recover between injections minimises reaction
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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.
Accessing Mounjaro in the UK: NHS vs Private Routes
NHS Access: Mounjaro is available through NHS specialist weight management services (tier 3), but availability varies significantly by region. You'll need a GP referral and may face waiting lists of several months. Once prescribed, you pay the standard prescription charge (£9.90 unless exempt). Private Access: You can access Mounjaro without NHS referral through a GPhC-registered online pharmacy. After a brief online clinical assessment with a UK-licensed prescriber, your prescription is issued if clinically appropriate. Private costs range from £129–£320 monthly depending on dose and provider. Both routes provide the same medication — your choice depends on waiting times and budget.
- 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.
Does Mounjaro bruising mean I should stop the injections?
No. Injection site bruising is a common, temporary side effect that typically fades within 1–2 weeks. It does not mean the medication is harming you. If bruising is severe, persists beyond 3 weeks, or shows signs of infection (increasing redness, warmth, pus), contact your GP or prescriber.
Will bruising affect my NHS prescription cost or eligibility?
No. Bruising is a documented common side effect and will not affect your NHS eligibility, specialist assessment, or prescription cost. Your NHS prescription will cost £9.90 (unless you're exempt) regardless of whether you experience bruising.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129 to £320 per month depending on your dose and the pharmacy. Starting doses (2.5 mg) cost less than higher maintenance or maximum doses (15 mg). Prices may vary slightly between providers — it's worth comparing GPhC-registered pharmacies for the best value.
How can I reduce bruising when injecting Mounjaro?
Rotate your injection sites weekly (stomach, thigh, upper arm), allow at least 7 days between injections at the same site, and ensure your skin is clean and dry before injecting. Avoid injecting into areas with existing bruising. Some people find applying a cold compress briefly after injection helps reduce bruising.
Should I choose NHS or private access for Mounjaro?
Choose NHS if you can access specialist services and accept waiting times — it's cheaper (£9.90 per prescription). Choose private if you want faster access and can afford £129–£320 monthly. Both provide genuine, licensed Mounjaro from UK-regulated pharmacies. Your GP can advise on NHS availability in your area.
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.