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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What Is Mounjaro's Golden Dose and How Much Does It Cost in the UK?
The "golden dose" of Mounjaro refers to the maximum 15mg weekly injection—the highest tirzepatide dose available in the UK. This term is used colloquially because 15mg typically produces the greatest average weight loss in clinical trials. However, not everyone needs the maximum dose; most people reach maintenance on lower doses (5mg, 10mg, or 12.5mg). Accessing Mounjaro in the UK involves either NHS specialist referral or private prescription routes, both with different costs and timelines. Understanding your options helps you make an informed decision about this prescription-only weight management 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.
Mounjaro 15mg Cost and Private Access in the UK
Private Mounjaro prescriptions in the UK typically cost between £140 and £320 per month, depending on which dose you're prescribed and which GPhC-registered pharmacy dispenses it. The 15mg "golden dose" sits at the higher end of this range because it contains the maximum amount of tirzepatide per injection. Each KwikPen contains four weekly doses (one month's supply). Prices vary between private providers due to different sourcing and overhead costs—always compare options across licensed pharmacies before committing. To access private Mounjaro, you'll need an online clinical assessment with a UK-licensed prescriber. They'll review your weight, BMI, health history, and any medications to confirm you're eligible. Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses before consultation.
- Typical private cost: £140–£320 per month depending on dose
- Each KwikPen (4 weeks): one injection per week
- Requires UK prescriber assessment and prescription
- Dispensed by GPhC-registered online pharmacy
- Payment required upfront before supply
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 vs Private: Access Routes and What to Expect
The NHS route is free but involves waiting for a referral to a specialist tier 3 weight management service—which can take months or longer depending on your region. The private route is faster (often assessed within days) but requires payment. For UK adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, both routes may be available. NHS prescribers now include Mounjaro (tirzepatide) as an option, though availability is patchy across different NHS integrated care boards. Most private online consultations take 24–48 hours for a decision. During your assessment, the prescriber checks whether Mounjaro is suitable based on your individual health profile, medical history, and any drug interactions. If approved, your prescription is sent to a UK pharmacy for dispatch.
- 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's 15mg dose the best for weight loss?
Clinical trials showed 15mg produces the highest average weight loss (around 20.9% of body weight), but individual results vary significantly. Many people achieve excellent results on 10mg or 12.5mg doses. Your prescriber will decide the right dose for you based on tolerance, response, and health factors. Starting low and titrating up minimises side effects.
Can I get Mounjaro free on the NHS in the UK?
Yes, if you're referred to an NHS specialist tier 3 weight management service and approved for tirzepatide. However, availability is limited and varies by region. Many areas have long waiting lists. Ask your GP about NHS tier 3 referral, but private routes are often faster if cost isn't prohibitive.
Why is private Mounjaro so expensive compared to other countries?
UK private prices reflect pharmacy costs, prescriber fees, and supply chain expenses. Tirzepatide is a complex medication requiring cold-chain storage and specialist handling. Importing from abroad is illegal in the UK—always use UK-licensed pharmacies with proper prescriptions to ensure safety and quality.
How long does it take to reach the 15mg "golden dose"?
Mounjaro dose escalation takes a minimum of 20–24 weeks. You start on 2.5mg and increase every 4 weeks (2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg). This gradual approach lets your body adjust and reduces gastrointestinal side effects. Many people stop escalating before reaching 15mg.
What happens after I reach my maintenance dose?
Once you've reached a dose that works for you—whether that's 5mg, 10mg, or 15mg—you'll continue that weekly injection as long as you're benefiting from it. Your prescriber will monitor your progress regularly. If you stop Mounjaro, weight regain may occur, so the medication is typically ongoing if you wish to maintain weight loss.
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.