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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Weight Loss a UK pharmacy: UK Prescription Options & Lifestyle Support
Weight loss a UK pharmacy refer to prescription medications and structured support that help with weight management in the UK. If you're looking to lose weight, there are several evidence-based options available — from NHS-approved injections like Mounjaro and Wegovy to lifestyle programmes supported by your GP. This guide covers what's available, who's eligible, and how to start the conversation with your healthcare provider about weight management support.
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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.
UK-Licensed Weight Loss Medications: What's Available?
Three prescription medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 receptor agonist; and Saxenda (liraglutide), also a GLP-1 agonist given daily rather than weekly.
Clinical trial data shows these medications may help achieve meaningful weight loss when used alongside reduced-calorie diet and increased physical activity. In SURMOUNT trials, tirzepatide helped participants lose an average of 15–21% of their body weight at maximum dose. Semaglutide (Wegovy) showed average weight loss of around 15% in STEP trials. Individual results vary significantly, and these medications are prescription-only, requiring a clinical assessment before being prescribed.
Use our free GLP-1 weight loss calculator above to estimate potential weight loss at different doses, and calculate your BMI to understand your starting point for weight management in the UK health system.
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: How to Get Started
NHS route: Weight loss medication is available through NHS specialist (tier 3) weight management services, but access varies significantly by region. Your GP can refer you, though waiting lists can be lengthy. Ask your GP about your local NHS weight management service and eligibility based on your BMI and any weight-related health conditions.
Private route: Licensed prescribers offer consultations and prescriptions through regulated channels, often with faster access than NHS services. Both routes require clinical assessment to confirm you meet eligibility criteria — typically a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea.
Use our free weight converter to check your weight in kg if you need to confirm your eligibility category, and speak with your GP today about which option suits you best.
- 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 does "weight loss a UK pharmacy" mean in UK healthcare?
"Weight loss a UK pharmacy" is an informal term for prescription weight management medications and structured support programmes. In the UK, this typically refers to GLP-1 and GIP/GLP-1 receptor agonist injections like Mounjaro, Wegovy, and Saxenda, which are prescribed alongside lifestyle changes to support sustainable weight management.
Am I eligible for prescription weight loss medication in the UK?
Eligibility typically requires a BMI of 30 or above, or 25–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea). Adults of South Asian, Chinese, Black African, or Black Caribbean backgrounds may have lower BMI thresholds. Your GP or a licensed prescriber can assess your individual eligibility during a consultation.
What's the difference between NHS and private weight loss medication in the UK?
NHS weight loss medication is provided through specialist weight management services (tier 3) via GP referral, but availability and waiting times vary by region. Private prescribers offer faster access through regulated consultations. Both require the same clinical assessment; the main difference is access speed, cost, and your healthcare team.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy, achieved over several months alongside dietary changes and physical activity. However, individual results vary significantly. Your progress tracker can help monitor your personal weight loss journey once you start treatment.
What should I discuss with my GP about weight loss medication?
Ask about your eligibility based on your BMI and health conditions, NHS specialist service availability in your area, what lifestyle changes are recommended, potential side effects, and whether prescription medication is appropriate for you. Bring your weight and height (or calculate your BMI using our free calculator) to make the conversation more concrete.
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.