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
What Does Your Pharmacist Do with Mounjaro?
A pharmacist plays a crucial role in your Mounjaro journey in the UK. Whether you're accessing tirzepatide through NHS specialist services or a private online prescription, your pharmacist will dispense your medication, explain how to use your KwikPen correctly, check for drug interactions, and monitor for side effects. Understanding your pharmacist's role helps you get the most from your prescription and spot potential issues early. Your pharmacist is your first point of contact for medication questions between appointments with your GP or prescriber.
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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.
Pharmacist Responsibilities in Mounjaro Treatment
Your pharmacist is responsible for several key aspects of your Mounjaro treatment in the UK. They will check your prescription for accuracy and verify it's been issued by a UK-licensed prescriber. They'll dispense the correct dose and ensure you receive your KwikPen with clear storage instructions — Mounjaro must be kept in the fridge at 2–8°C unopened, or at room temperature below 30°C for up to 30 days after first use. Your pharmacist will counsel you on injection technique, showing you how to use your KwikPen, rotate injection sites (stomach, thigh, or upper arm), and properly dispose of used pens. They'll also screen for drug interactions, particularly with oral contraceptives and diabetes medications, and identify any contraindications to Mounjaro based on your medical history. Most importantly, they'll advise you on managing common side effects like nausea and diarrhoea, and explain when to seek urgent medical advice — for example, severe stomach pain that could indicate pancreatitis.
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 Mounjaro Pharmacist Access in the UK
Accessing Mounjaro through NHS specialist weight management services means your pharmacist works within the NHS tier 3 or tier 4 pathway. Your GP refers you to a specialist multidisciplinary team who assess your eligibility and prescribe Mounjaro following NICE guidance. The NHS pharmacist will dispense your medication at an NHS hospital pharmacy and provide NHS-funded support. Private access involves obtaining a prescription from a UK-licensed prescriber through an online consultation, which is then dispensed by a GPhC-registered pharmacy. Private pharmacists offer the same professional standards and safeguarding but may provide additional convenience through home delivery. Both routes require your pharmacist to verify you meet eligibility criteria: BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions like type 2 diabetes or cardiovascular disease.
- 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 my community pharmacist prescribe Mounjaro?
No. Mounjaro is a prescription-only medicine that must be prescribed by a doctor (GP or specialist) or a nurse prescriber with appropriate training, not by a pharmacist. Your community pharmacist can dispense the prescription but cannot issue it. NHS access requires a specialist assessment; private prescriptions come from UK-licensed doctors via online consultation.
What should I tell my pharmacist about Mounjaro?
Tell your pharmacist about all medications you take (especially oral contraceptives and diabetes drugs), any allergies, any history of pancreatitis or gallbladder problems, and whether you're pregnant or breastfeeding. Be honest about any side effects you've experienced. This helps your pharmacist spot interactions and provide tailored advice.
Can my pharmacist adjust my Mounjaro dose?
No. Only your prescriber can adjust your Mounjaro dose. Your pharmacist's role is to dispense the dose your prescriber has indicated and counsel you on how to use it. Dose increases happen every 4 weeks minimum and must be managed by your doctor or specialist nurse, not your pharmacist.
What if my pharmacist says I can't have Mounjaro?
Your pharmacist may flag concerns if there are drug interactions, allergies, or contraindications on your record. They should explain their concern and advise you to discuss this with your prescriber. Your prescriber can then decide whether to proceed, change your medication, or adjust dosing.
Where do I get Mounjaro — pharmacy or hospital?
On the NHS, Mounjaro is dispensed at hospital pharmacies within specialist weight management services. Privately, it's dispensed by GPhC-registered online pharmacies and delivered to your home. Either way, your pharmacist has a professional duty to ensure safe prescribing and use.
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.