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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How to Order 5mg Mounjaro in the UK
If you're asking how to order 5mg Mounjaro, it's important to understand that this medication is prescription-only in the UK and cannot be purchased over the counter. The 5mg dose is typically the first maintenance dose in the Mounjaro dose titration schedule — you'll generally start at 2.5mg for the first four weeks, then progress to 5mg in week five. To obtain Mounjaro, you need a prescription from a UK-licensed prescriber following a clinical assessment. This guide explains the ordering process, eligibility requirements, and what to expect when starting this tirzepatide injection.
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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.
Getting a Mounjaro Prescription in the UK
Mounjaro (tirzepatide) is a prescription-only, once-weekly injectable medication licensed in the UK for weight management in adults. You cannot simply "order" Mounjaro like an over-the-counter product — a qualified prescriber must assess your eligibility first.
Two main routes to access Mounjaro in the UK:
- NHS specialist services: Referral through your GP to a tier 3 or 4 weight management service. Availability and waiting times vary significantly by region (ICB). Access is typically limited to people with a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or sleep apnoea.
- Private prescribing: Online consultation with a UK-licensed prescriber (doctor or nurse prescriber). If deemed clinically appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy. This route does not require NHS referral and is often faster than NHS specialist services.
Whichever route you choose, a clinical assessment is mandatory before you receive a prescription. This protects your safety and ensures Mounjaro is suitable for your individual health profile.
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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.
The 5mg Dose and Mounjaro Dose Titration
The 5mg dose is not your starting dose — Mounjaro uses a gradual dose titration schedule. You'll begin at 2.5mg once weekly for weeks 1–4, then increase to 5mg in week 5. Each KwikPen contains four weekly doses, so your first prescription covers the 2.5mg induction phase. Your prescriber will typically issue a new prescription for 5mg pens in week five, assuming no concerning side effects have emerged.
The 5mg dose is usually well-tolerated and represents the first maintenance dose for many patients. Clinical trial data shows that average weight loss by week 21–26 at 5mg was approximately 15% of body weight — though individual results vary considerably. Some people progress to higher doses (7.5mg, 10mg, 12.5mg, or 15mg), whilst others find 5mg provides sufficient results alongside a reduced-calorie diet and increased physical activity.
To check your personal weight management needs, use our free BMI calculator above to determine your current BMI category — this is often a starting point in discussions with prescribers. You can also try our GLP-1 weight loss calculator to estimate potential weight loss outcomes at different Mounjaro 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.
Can I order 5mg Mounjaro online without a prescription?
No. Mounjaro is prescription-only in the UK and cannot be legally supplied without a valid prescription from a UK-licensed prescriber. Any supplier offering Mounjaro without requiring a clinical assessment is operating illegally. Always use registered pharmacies and licensed prescribers.
How much does 5mg Mounjaro cost in the UK?
NHS cost varies by region and is typically covered by specialist weight management services where available. Private prescriptions usually cost between £150–£250 per dose (four-week supply) depending on the provider and dose. Always confirm costs with your prescriber or pharmacy before starting.
What's the difference between 5mg Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1-only agonist. Mounjaro's dual mechanism may support slightly higher average weight loss in clinical trials, but both are prescription-only and require clinical assessment. The choice depends on your individual health profile and prescriber recommendation.
Will my GP prescribe 5mg Mounjaro directly?
In most cases, no. GPs typically refer patients to specialist tier 3 weight management services through the NHS. However, some private GP services and online prescribing services (following clinical assessment) will prescribe Mounjaro directly if you meet eligibility criteria. Ask your GP about local NHS pathways or private options in your area.
Are there side effects at the 5mg Mounjaro dose?
Common side effects at 5mg include nausea, diarrhoea, constipation, and stomach pain — though not everyone experiences them. These often ease as your body adjusts. Serious side effects are rare but include severe stomach pain (possible pancreatitis) and allergic reactions. Always report any concerning symptoms to your prescriber immediately.
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.