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 Headache — UK Access and Cost Guide
Headaches are a common side effect reported by people taking Mounjaro (tirzepatide) in the UK, though not everyone experiences them. If you're considering Mounjaro for weight management or wondering about access costs in the UK, this guide covers what headaches mean, how to manage them, and the practical steps to accessing this prescription-only injection through NHS specialist services or private prescribing routes. Understanding both the side effects and the cost structure helps you make an informed decision about whether Mounjaro is right for you.
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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 Costs and Access in the UK
NHS access: Mounjaro is approved by NICE for use within NHS specialist weight management services (tier 3/4). However, NHS access is not available through standard GP prescription — you must be referred to a dedicated weight management service. Waiting lists vary significantly by region (ICB area), and in many parts of the UK, waits can exceed 12–18 months. NHS provision is free at point of use once you access the service.
Private prescription costs: Through private online prescribing, Mounjaro costs typically range from £129 to £320 per month, depending on your dose and the provider. A single KwikPen (4-week supply) contains four pre-filled doses and covers four weeks of once-weekly injections. Initial consultations usually cost £20–£50, and repeat prescriptions are often cheaper than the first. Prices vary between GPhC-registered pharmacies, so it's worth comparing options. The dose titration process — starting at 2.5 mg and escalating over weeks — means your costs may be lower initially before reaching maintenance doses of 10–15 mg.
Private vs NHS timeline: Private access is typically available within days of online consultation and approval, whereas NHS referral routes can take months or years depending on your local service availability.
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.
Understanding Mounjaro Headaches and Managing Them
Headaches are reported as a common side effect of Mounjaro in clinical trials and real-world UK use, affecting up to 1 in 10 people. They are usually mild to moderate and often improve after the first few weeks as your body adjusts to the medication. Headaches may be linked to dehydration, changes in blood sugar, or the dose titration process itself. Most people find that staying well-hydrated, eating regular meals (even in smaller portions), and managing the GI side effects that sometimes accompany Mounjaro can help reduce headache severity. If headaches persist or worsen, contact your prescriber — they may adjust your dose or suggest pain relief strategies. Serious headaches combined with vision changes or severe stomach pain require urgent medical attention and should be reported to your GP or NHS 111.
Use our free GLP-1 weight loss calculator to explore potential outcomes at different Mounjaro doses, and our BMI calculator to track your baseline and progress throughout treatment.
- 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.
How much does Mounjaro cost per month in the UK?
Private prescription costs typically range from £129 to £320 per month depending on your dose and provider. A single KwikPen (4-week supply) contains four pre-filled doses. NHS access is free but requires referral to a specialist weight management service, with waits often exceeding 12 months in many regions.
Is Mounjaro headache a serious side effect?
Headaches are common but usually mild to moderate and often improve within the first few weeks. They're not typically serious, but if combined with vision changes, severe stomach pain, or persistent after 4 weeks, contact your GP or NHS 111 for guidance.
How do I access Mounjaro privately in the UK?
Through GPhC-registered online pharmacies offering private prescribing. Complete an online health questionnaire, consult with a UK-licensed prescriber, and if approved, receive a prescription dispensed by the pharmacy. The process typically takes 24–48 hours from consultation to dispatch.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is NICE-approved for NHS use through specialist tier 3/4 weight management services. However, you need a GP referral and may wait 12–18 months depending on your region. Once approved, it's free to receive through the NHS.
What's the difference between Mounjaro and Wegovy in terms of cost?
Both are prescription-only with similar private costs (£129–£320/month). Mounjaro is a GIP+GLP-1 dual agonist with maximum 15 mg dose, while Wegovy is GLP-1 only with maximum 2.4 mg dose. Mounjaro dose titration starts lower, potentially reducing initial costs. Consult a prescriber about which suits your needs.
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.