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 5mg in the UK — What You Need to Know
Mounjaro 5mg is the first dose escalation step in tirzepatide treatment for weight management in UK adults. This dose is typically used after the initial 2.5mg starting phase. Understanding how to access Mounjaro 5mg — whether through the NHS or privately — and what the actual costs are, can help you make informed decisions about your weight management options.
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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.
NHS vs Private Access for Mounjaro 5mg
NHS access: Mounjaro (tirzepatide) is approved by NICE for use within specialist NHS weight management services, but this route involves significant barriers. You must be referred by your GP to a tier 3 weight management service, which typically requires meeting specific BMI thresholds (BMI 30 or above, or BMI 27–29.9 with weight-related health conditions). Waiting lists for NHS tier 3 services can extend several months to over a year in many regions. When prescribed through the NHS, Mounjaro costs the NHS approximately £120–140 per month at standard doses.
Private access: Mounjaro is available through UK-licensed online prescribing services following a brief clinical assessment. Private prescriptions typically cost £150–280 per month depending on dose and provider. The 5mg dose (week 5–8 adjustment dose) is supplied as a single KwikPen containing four weekly injections. No NHS referral is needed for private prescribing — you can access treatment within days rather than months.
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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.
Mounjaro 5mg Eligibility and Dose Titration
The 5mg dose is a mandatory intermediate step in Mounjaro treatment — you cannot start at this dose directly. All patients begin at 2.5mg for weeks 1–4, then escalate to 5mg for weeks 5–8. You must spend at least 4 weeks on 5mg before increasing further, allowing your body to adjust to the medication. Your prescriber may recommend staying at 5mg longer if side effects are manageable or if weight loss progress is satisfactory. The dose titration schedule is evidence-based and applies whether you're receiving Mounjaro through the NHS or privately. Use our GLP-1 weight loss calculator to estimate potential weight loss outcomes at different doses.
- 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 5mg cheaper through the NHS than private prescriptions?
When dispensed through the NHS, Mounjaro costs the NHS approximately £120–140 per month but patients pay nothing at the point of dispensing (free on prescription). Privately, you pay approximately £150–280 per month depending on the provider. However, accessing Mounjaro through the NHS tier 3 route often requires waiting many months, whereas private routes typically provide access within 1–2 weeks.
Can I request just the 5mg dose without starting at 2.5mg?
No. Mounjaro treatment always begins at 2.5mg for the first 4 weeks. The 5mg dose is the mandatory second step in the dose titration schedule. This approach allows your body to adjust to the medication and helps manage side effects. Your prescriber cannot skip this step regardless of your BMI or health status.
What happens if I stay on Mounjaro 5mg for longer than 4 weeks?
You can remain on 5mg beyond 4 weeks if you and your prescriber decide this is appropriate. Some patients see good weight loss results or tolerate the dose well and choose not to escalate further. Others escalate after 4 weeks as planned. The decision to escalate depends on your individual response, side effects, and weight loss progress.
Does Mounjaro 5mg come in different packaging options?
Mounjaro 5mg is only available as a pre-filled KwikPen injection device. Each pen contains four doses (one month supply of weekly injections). You cannot buy smaller quantities or different formats. Each new prescription requires a new pen even if you don't use all four doses.
How do I know if I'm eligible for Mounjaro 5mg through my NHS GP?
You must have a BMI of 30 or above, or 27–29.9 with a weight-related condition like type 2 diabetes or high blood pressure. You'll need to be referred to your local tier 3 specialist weight management service by your GP. Availability and exact criteria vary by region. Your GP can advise whether referral is appropriate for your circumstances.
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.