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
Can a GP Prescribe Mounjaro in the UK?
Your GP can prescribe Mounjaro (tirzepatide), but access through the NHS is limited and varies significantly by region. Most GPs refer eligible patients to specialist tier 3 weight management services rather than prescribing directly. Private prescription routes via online clinical assessment offer faster access, though at personal cost. Understanding your options — NHS referral, specialist services, or private prescription — helps you make an informed decision about accessing this dual GIP and GLP-1 receptor agonist medication.
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.
NHS vs Private Access Routes for Mounjaro
NHS Route: Your GP cannot typically prescribe Mounjaro directly within primary care. Instead, you'll need referral to a specialist tier 3 or tier 4 weight management service. These services are accessed through your GP, but referrals vary in availability and waiting times can be substantial — from weeks to years depending on your area and NHS ICB (Integrated Care Board) resources.
- Referral must be made by your GP following NHS guidelines
- Assessment by specialist weight management team determines eligibility and suitability
- Once approved, the specialist service prescribes and monitors treatment
- Cost to you: nil — provided by NHS
- Mounjaro KwikPen is dispensed by NHS pharmacy
Private Route: Access Mounjaro privately via an online clinical assessment with a UK-licensed prescriber. This route bypasses NHS waiting lists and is available without GP referral, though you pay directly.
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.
Private Mounjaro Costs and What to Expect
Private tirzepatide (Mounjaro) costs typically range from £129–£320 per month depending on dose and private provider. Starting dose (2.5 mg) is usually cheaper; maximum dose (15 mg) costs more. Most private providers offer per-dose pricing or monthly subscriptions. Your prescriber conducts an online health assessment before issuing a prescription — you'll answer questions about your weight, BMI, medical history, and medications to determine suitability. The prescription is then sent to a GPhC-registered pharmacy for dispensing. Expect the full assessment-to-delivery process to take 3–7 working days. Private prescribing requires no NHS involvement, making it faster than specialist referral routes, though individual costs apply.
- 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.
Do I need my GP's permission to get a private Mounjaro prescription?
No. Private prescription pathways are independent of your GP. You can access private clinical assessment and prescription without involving your GP. However, it's good practice to inform your GP you're considering or starting Mounjaro so they can monitor your health alongside treatment.
What eligibility criteria does a private prescriber use for Mounjaro?
Private prescribers typically follow UK clinical guidelines: BMI ≥30 or BMI 27–29.9 with weight-related comorbidities (type 2 diabetes, hypertension, cardiovascular disease). Ethnicity-adjusted thresholds may apply for South Asian, Chinese, or Black African/Caribbean adults. Individual health factors are assessed during your online consultation.
Is private Mounjaro prescription legally valid in the UK?
Yes, if prescribed by a UK-registered doctor and dispensed by a GPhC-registered pharmacy. Always verify the prescriber's registration via the GMC (General Medical Council) and the pharmacy's registration via the GPhC (General Pharmaceutical Council) before proceeding.
How does Mounjaro compare to Wegovy in terms of NHS access?
Both face similar NHS access barriers — specialist referral and waiting lists. However, Mounjaro (tirzepatide) offers dual GIP and GLP-1 action versus Wegovy's (semaglutide) single GLP-1 mechanism. Clinical trials suggest Mounjaro may support slightly higher average weight loss, though individual results vary significantly.
Can I switch from private Mounjaro to NHS treatment?
Potentially, but continuity is not assured. If your NHS specialist service approves you for tirzepatide, you could transfer to NHS dispensing. However, NHS eligibility and regional availability vary. Discuss transition plans with both your private prescriber and NHS team if you wish to switch.
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.