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 Use Golden Dose Mounjaro — Complete UK Guide
The "golden dose" of Mounjaro refers to the dose that delivers optimal results for many users — typically between 10 mg and 15 mg weekly. However, Mounjaro is a prescription-only medicine, and the correct dose for you must be determined by your prescriber following a clinical assessment. This guide explains how Mounjaro dosing works in the UK, what the dose escalation process involves, and what you need to know about safe use. Always follow your prescriber's instructions carefully and discuss any concerns with them before using this medication.
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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.
Understanding Mounjaro Dosing and the Escalation Schedule
Mounjaro (tirzepatide) works through dose titration, meaning you start at a low dose and gradually increase it every 4 weeks. This approach helps your body adjust while allowing your prescriber to find the dose that works best for you.
- Week 1–4: 2.5 mg once weekly (starting dose)
- Week 5–8: 5 mg once weekly
- Week 9–12: 7.5 mg once weekly
- Week 13–16: 10 mg once weekly
- Week 17–20: 12.5 mg once weekly
- Week 21+: 15 mg once weekly (maximum dose)
The 10 mg to 15 mg range is often referred to as the "therapeutic range" where many users see significant weight loss. In clinical trials (SURMOUNT-1), participants on 15 mg Mounjaro achieved average weight loss of approximately 21% of their body weight over 72 weeks, alongside diet and exercise. However, your prescriber may recommend staying at a lower dose if you're experiencing side effects or achieving good results. Each dose is contained in a pre-filled KwikPen with 4 weekly injections.
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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.
How To Inject and Store Your Mounjaro Pen Safely
Mounjaro comes as a pre-filled KwikPen. Inject once weekly into the stomach (abdomen), upper thigh, or upper arm — rotate sites each week to prevent skin irritation. Before injecting, let the pen sit at room temperature for 15 minutes. Check the liquid is clear and colourless. Pinch the skin, insert the needle at a 90-degree angle, and hold for 6 seconds. Store unopened pens in a refrigerator at 2–8°C. After first use, you can keep the pen at room temperature (below 30°C) for up to 30 days. Never freeze. Dispose of the pen safely 30 days after first use. Track your injection dates so you don't miss doses — use our free progress tracker to log your weight and injections alongside your Mounjaro use.
- 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 "golden dose" of Mounjaro?
The golden dose typically refers to 10 mg to 15 mg weekly — the dose range where most users experience significant weight loss in clinical trials. However, the right dose for you is individualised and determined by your prescriber. Some users achieve excellent results at 10 mg, while others may need the full 15 mg. Your prescriber will guide you based on your response and any side effects.
Can I skip doses or adjust my Mounjaro dose myself?
No. Mounjaro is prescription-only, and your prescriber must supervise all dose changes. Never skip doses without medical guidance. If you miss a dose, take it within 4 days of the scheduled time. If it's been more than 4 days, skip that dose and take your next dose on schedule. Always contact your prescriber before making changes.
How long does it take to reach the golden dose?
It takes approximately 20 weeks (5 months) to progress from the starting dose (2.5 mg) to the maximum dose (15 mg), assuming you escalate every 4 weeks without delays. You stay at each dose for 4 weeks before increasing. Your prescriber may slow this timeline if you experience side effects or achieve good results at a lower dose.
What side effects might I experience at higher doses of Mounjaro?
Common side effects include nausea, diarrhoea, constipation, and stomach pain — these are typically most noticeable when escalating doses. They usually improve within a few days as your body adjusts. At higher doses (10+ mg), some users report increased appetite suppression and fatigue. Contact your GP if side effects persist or are severe. Many side effects reduce over time with consistent use.
Is Mounjaro available on the NHS, and how do I get a prescription?
Mounjaro is available through NHS specialist tier 3 weight management services, but access varies significantly by region and waiting times can be long. Private prescribing is also available through UK-licensed online prescribers following a clinical assessment. Eligibility typically requires a BMI of 30+ or 27+ with weight-related health conditions. Speak to your GP about your options, or visit MyWeightCheck to explore private routes. ```
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