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 Is Semaglutide Used For in the UK?
Semaglutide is a prescription-only GLP-1 receptor agonist used for weight management in UK adults. Available under the brand name Wegovy, semaglutide works by reducing appetite and helping you feel fuller after smaller meals. It's prescribed alongside a reduced-calorie diet and increased physical activity for adults with a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes or high blood pressure. Access in the UK varies significantly depending on whether you pursue NHS or private prescription routes.
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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.
Semaglutide Cost and Access in the UK
Private prescription costs: Semaglutide (Wegovy) through private online prescribing typically costs between £129 and £300 per month, depending on your dose and the provider. The 2.4mg maintenance dose — the standard therapeutic dose for weight management — usually costs between £180 and £250 per month. This price includes the clinical assessment, prescription, and dispensing from a GPhC-registered pharmacy. Your GP cannot currently prescribe Wegovy on the NHS outside specialist services, so private access bypasses waiting lists entirely.
- Starting doses (0.25–0.5mg) may cost slightly less, around £129–£150/month
- Higher doses (1.7–2.4mg) typically cost £180–£300/month depending on provider
- Initial online consultations usually cost £20–£50, though some providers include this in the overall cost
- Each KwikPen contains 4 doses (4 weeks of supply)
Costs can vary between private providers, so comparing quotes is worthwhile. All providers must be GPhC-regulated and work with UK-licensed prescribers.
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 for Semaglutide
NHS access: Semaglutide is available through NHS specialist weight management services (tier 3), but access is strictly limited and varies dramatically by region. Your GP must refer you to your local integrated care board (ICB) weight management service, and waiting times can be extremely long — in many areas, years. NHS provision focuses on those with the highest health risk.
Private access: Much faster and more accessible. You complete an online health questionnaire, have a consultation with a UK-licensed prescriber (usually via video or phone), and if approved, your prescription is sent to a GPhC-registered pharmacy. The entire process takes 3–7 days typically. Try our free GLP-1 weight loss calculator to explore potential outcomes before committing to treatment.
- 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 GP prescribe Wegovy on the NHS?
Outside of specialist tier 3 weight management services, no — most GPs cannot prescribe semaglutide for weight loss. You would need to be referred to a specialist NHS weight management service, which involves long waiting lists and regional variation. Private online prescription is much faster.
How much does semaglutide cost privately in the UK?
Private semaglutide costs typically range from £129–£300 per month depending on dose. The standard 2.4mg dose usually costs £180–£250/month. This includes the clinical assessment and prescription from a GPhC-registered pharmacy. Prices vary between providers.
What is semaglutide vs Ozempic — are they the same?
Both contain the same active ingredient (semaglutide from Novo Nordisk) but are licensed for different uses. Wegovy is licensed specifically for weight management in the UK, while Ozempic is licensed for type 2 diabetes. Using Ozempic for weight loss is off-label. Wegovy is the appropriate licensed option.
How do I get a private semaglutide prescription in the UK?
Contact a GPhC-registered online prescribing service, complete a health questionnaire, attend an online consultation with a UK-licensed prescriber, and if approved, your prescription is dispensed by the pharmacy. The process typically takes 3–7 days. You'll be assessed for eligibility based on BMI and health conditions.
Is semaglutide weight loss covered by the NHS?
Only through tier 3 specialist weight management services, which have strict criteria and long waiting lists. Most NHS trusts prioritise those with the highest health risk. Private prescription offers faster access but costs between £129–£300/month depending on dose and provider.
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.