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
How to Lose Weight with Pharmacy Support in the UK
Losing weight safely and sustainably often requires more than willpower alone. UK pharmacies play an important role in weight loss support by providing prescription weight management medications alongside lifestyle guidance. Whether through NHS weight management services or private consultations, pharmacies help assess your eligibility and monitor your progress. This guide explains the pharmacy-supported weight loss options available in the UK, how they work, and what to expect.
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.
Pharmacy Weight Loss Medication Options in the UK
Two main prescription weight loss medications are available through UK pharmacies: Mounjaro (tirzepatide) and Wegovy (semaglutide). Both are GLP-1 receptor agonist injections that help reduce appetite and support feeling fuller after smaller meals.
- Mounjaro: A dual GIP and GLP-1 agonist, dosed from 2.5 mg to 15 mg weekly. Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks alongside dietary changes.
- Wegovy: A GLP-1 agonist, dosed from 0.25 mg to 2.4 mg weekly. STEP trial data showed average weight loss of approximately 15% of body weight at the maximum dose.
Both require a prescription from a UK-licensed prescriber and a clinical assessment to confirm you're eligible. Access is available through NHS specialist tier 3 weight management services or private online consultations with GPhC-registered pharmacies. Individual results vary significantly — weight loss depends on the dose, your starting weight, diet, and physical activity levels. Try our free GLP-1 weight loss calculator to estimate potential results at different doses.
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.
Building a Complete Weight Loss Strategy with Pharmacy Support
Prescription medication alone is not enough for sustainable weight loss. Pharmacies provide weight loss support by combining medication with dietary guidance, physical activity encouragement, and progress monitoring. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week, which typically requires a calorie deficit of around 500 kcal per day. A 5–10% reduction in body weight can deliver meaningful health benefits, including lower blood pressure, improved blood sugar control, and reduced cardiovascular risk. Use our free progress tracker to log your weight loss journey, and calculate your BMI using our BMI calculator to monitor your health status throughout your weight loss. Your pharmacy or GP can also refer you to community weight management programmes or dietitian support for additional help.
- 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 I get weight loss medication from any UK pharmacy?
No. Weight loss medications like Mounjaro and Wegovy are prescription-only and require a clinical assessment from a UK-licensed prescriber. You can access them through NHS specialist weight management services (usually by GP referral) or private online consultations with GPhC-registered pharmacies. Your prescriber will assess your eligibility based on your BMI, health conditions, and medical history.
How long does pharmacy weight loss medication take to work?
Weight loss typically becomes noticeable within 4–8 weeks, though individual timelines vary. The medication is gradually increased over 16–20 weeks to minimise side effects. Most clinical trial data comes from studies of 68–72 weeks of treatment. Sustainable weight loss takes time — patience and consistency with diet and exercise matter as much as the medication itself.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Ozempic is approved for type 2 diabetes (doses up to 2 mg) and is not licensed for weight loss in the UK. Wegovy is specifically licensed for weight management at higher doses (up to 2.4 mg). Using Ozempic for weight loss is off-label. Always ask your prescriber which medication they're recommending and why.
What if I have side effects from weight loss medication?
Common side effects include nausea, diarrhoea, and stomach discomfort — usually temporary and mild. Tell your pharmacy or prescriber about any side effects; they may adjust your dose or suggest timing changes. Serious side effects like severe stomach pain require immediate medical attention. Never stop medication without consulting your prescriber.
How much does pharmacy weight loss medication cost?
NHS costs vary by region and availability — specialist services may provide treatment free, though waiting lists can be very long. Private pharmacy costs range from approximately £129–£320 per month depending on dose and provider. Your GP can discuss NHS options; private pharmacies can provide transparent pricing during your online consultation.
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.