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
Free tracker included with every download this week
Understanding Mounjaro Strength and Doses in the UK
Mounjaro (tirzepatide) comes in six different strengths, ranging from 2.5mg to 15mg per week. If you're considering this prescription injection through the NHS or privately in the UK, understanding how doses work — and how they escalate — is essential. This guide explains each strength, how the titration schedule works, and what NHS and NICE guidance says about Mounjaro prescribing in the UK.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Doses and How They Escalate in the UK
Mounjaro is available in the following weekly strengths:
- 2.5mg — starting/adjustment dose (weeks 1–4)
- 5mg — first maintenance dose (weeks 5–8+)
- 7.5mg — escalation option (weeks 9–12+)
- 10mg — escalation option (weeks 13–16+)
- 12.5mg — escalation option (weeks 17–20+)
- 15mg — maximum dose (week 21+)
Each dose is delivered as a once-weekly injection using a KwikPen device. You must spend a minimum of 4 weeks on each dose before escalating to the next strength. This gradual titration approach helps your body adjust and reduces side effects like nausea. If you experience troublesome side effects at any strength, your prescriber may keep you on that dose longer or not escalate further — there is no requirement to reach the maximum strength. Clinical trial data (SURMOUNT-1) showed that participants on higher doses (10mg and 15mg) achieved greater average weight loss, though individual results vary significantly.
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 Eligibility and Prescribing Context for Mounjaro in the UK
NICE approved tirzepatide (Mounjaro) for use within NHS specialist weight management services. However, NHS access is not through standard GP prescription — you must be referred to a tier 3 or tier 4 specialist weight management service. Eligibility typically requires a BMI of 30kg/m² or above, or 27–29.9kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply. Availability varies significantly by region (Integrated Care Board), and waiting lists for NHS specialist services can be lengthy — often months to over a year in some areas. Private prescribing through licensed UK providers offers faster access without NHS referral, though at a cost. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and our BMI calculator to check your current eligibility status.
- 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.
What is the starting dose of Mounjaro in the UK?
The starting dose is 2.5mg once weekly. You stay on this dose for weeks 1–4 to allow your body to adjust. After 4 weeks, your prescriber may escalate you to 5mg or keep you on 2.5mg if needed. The escalation depends on how you tolerate the medication and any side effects you experience.
Can I stay on a lower dose of Mounjaro if it's working for me?
Yes, absolutely. There is no requirement to reach the maximum 15mg dose. If you're achieving good results and tolerating a lower dose well — such as 5mg or 7.5mg — your prescriber may recommend staying at that strength. Weight loss outcomes vary by individual, and a lower dose may be sufficient for your goals.
How much weight loss can I expect at different Mounjaro strengths?
SURMOUNT-1 clinical trials showed average weight loss of approximately 15% at 5mg, 19.5% at 10mg, and 20.9% at 15mg over 72 weeks, alongside diet and exercise. However, individual results vary significantly. Some people lose more, some less. Your prescriber will monitor your progress and adjust your dose accordingly.
Is Mounjaro available on the NHS in my area?
Availability varies by region in the UK. Most areas now offer tier 3 specialist weight management services where Mounjaro may be prescribed, but waiting lists are long — often 6–12 months. Contact your GP for referral information, or ask about private prescribing options if NHS waiting times are a concern.
What's the difference between Mounjaro strength and Wegovy strength?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are different medications with different mechanisms and dose ranges. Mounjaro's maximum is 15mg weekly; Wegovy's maximum is 2.4mg weekly. They cannot be directly compared dose-for-dose. Your prescriber will recommend the most appropriate option based on your health profile and eligibility.
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.