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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Semaglutide Doses For Weight Loss — UK Guide
Semaglutide is a once-weekly weight loss injection available in the UK under the brand name Wegovy. It comes in five different doses, ranging from 0.25mg to 2.4mg, with doses increased gradually over 16 weeks. This guide explains each dose level, typical costs in the UK private market, and how to access semaglutide through the NHS or private prescription routes. Understanding your options helps you make an informed decision with your healthcare provider.
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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 Dose Levels And UK Private Costs
Semaglutide is a GLP-1 receptor agonist that helps regulate appetite and support weight loss alongside a reduced-calorie diet and increased physical activity. In the UK, Wegovy comes in five dose strengths administered as a once-weekly injection:
- 0.25mg — starting dose (weeks 1–4), typically £129–£160/month
- 0.5mg — escalation dose (weeks 5–8), typically £145–£175/month
- 1mg — escalation dose (weeks 9–12), typically £160–£190/month
- 1.7mg — escalation dose (weeks 13–16), typically £180–£220/month
- 2.4mg — maintenance and maximum dose (week 17 onwards), typically £195–£280/month
Each dose is injected subcutaneously once per week. Private prescription costs vary significantly by provider and dose — these are approximate market ranges for GPhC-registered pharmacies. Clinical trials showed that the 2.4mg maintenance dose resulted in an average weight loss of approximately 14.9% body weight over 68 weeks, though individual results vary considerably.
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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 Access Versus Private Prescription Routes
Accessing semaglutide in the UK involves two main routes. NHS access is through specialist tier 3 weight management services (usually following GP referral), though availability varies significantly by region and waiting times can be lengthy — many areas have multi-month waiting lists. Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or cardiovascular disease.
Private access is faster: complete an online consultation with a UK-licensed prescriber, receive a prescription if clinically appropriate, and collect from a GPhC-registered pharmacy. No NHS referral is needed. Calculate your potential weight loss progression using our GLP-1 weight loss calculator, and track your progress with our free progress tracker once you start treatment. Always inform your prescriber of all medications, as semaglutide may affect oral contraceptive absorption.
- 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.
How long does it take to reach the 2.4mg maintenance dose of semaglutide?
Typically 16 weeks. You start at 0.25mg for four weeks, then increase by 0.25–0.5mg every four weeks depending on the dose level. Your prescriber may adjust your schedule based on how you tolerate each dose.
What is the difference between semaglutide and Ozempic?
Both contain semaglutide, but Ozempic (up to 2mg) is licensed for type 2 diabetes management, while Wegovy (up to 2.4mg) is licensed specifically for weight management in UK adults. Ozempic is not approved for weight loss in the UK.
Can I get semaglutide on the NHS in the UK?
Yes, through specialist tier 3 weight management services following GP referral. However, availability and waiting times vary widely by region. Private prescription options offer faster access if you meet the eligibility criteria and can afford the cost.
How much does semaglutide cost privately in the UK?
Private costs range from approximately £129–£280 per month depending on the dose and provider. Starting doses (0.25–0.5mg) are cheaper, while higher maintenance doses cost more. Always check with providers for current pricing.
What should I expect during an online consultation for semaglutide?
You'll answer questions about your medical history, current medications, weight, height, and BMI. A UK-licensed prescriber reviews your information to assess suitability. If approved, you receive a prescription sent to a GPhC-registered pharmacy for dispensing.
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.