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
Weight Loss Doctors in the UK — Medication Options
If you're looking for professional support with weight management in the UK, your GP or a specialist weight loss doctor can discuss prescription medication options with you. Several licensed weight loss medications are now available on the NHS and through private prescribing, alongside lifestyle changes. Understanding what's available, who's eligible, and how to access these treatments is the first step towards finding the right approach for your health.
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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
Three prescription weight loss medications are currently licensed in the UK for adults with excess weight. Mounjaro (tirzepatide) is a once-weekly injection that activates two hormone pathways, helping regulate appetite and support weight loss. Wegovy (semaglutide) is also a once-weekly injection that works via the GLP-1 pathway. Saxenda (liraglutide) is a daily injection option. Clinical trials have shown that GLP-1 weight loss medication can help adults lose an average of 15–21% of their body weight when combined with a reduced-calorie diet and increased physical activity — though individual results vary significantly. Your weight loss doctor will assess which option may be suitable for you based on your personal health profile, current BMI, and weight-related health conditions. Use our free GLP-1 weight loss calculator above to understand potential outcomes 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.
NHS vs Private Access for Weight Loss Medication
In the UK, weight loss doctors operate in two settings: NHS specialist weight management services and private online prescribing. NHS access requires referral from your GP to a tier 3 weight management clinic, where a specialist team assesses eligibility and prescribes medication. Availability and waiting times vary significantly by region. Private access is faster — you can have an online consultation with a UK-licensed prescriber, and if eligible, medication is dispensed by a registered pharmacy within days. Both routes require a prescription and clinical assessment. Your GP can advise whether NHS or private routes suit your circumstances, and discuss whether prescription weight loss medication is appropriate for your specific health needs and weight management goals.
- 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 qualifies me for weight loss medication from a UK doctor?
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, heart disease). Lower BMI thresholds apply for South Asian, Chinese, Black African, or Black Caribbean adults. Your doctor assesses individual circumstances.
How do I find a weight loss doctor on the NHS?
Ask your GP for a referral to your local tier 3 weight management service. They'll assess you and discuss prescription options if appropriate. NHS services are free but may have waiting lists. Availability varies by region.
Can I get weight loss medication privately?
Yes. Many UK GPhC-registered online services offer consultations with licensed prescribers. If you're eligible, a prescription is issued and medication dispensed by a registered pharmacy. You'll pay privately — costs vary by medication and dose.
How much weight will I lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight with GLP-1 medications, but results vary significantly between individuals. Medication works best alongside dietary changes and increased physical activity. Your progress tracker can help you monitor your personal journey.
What happens if weight loss medication isn't right for me?
Your weight loss doctor will discuss alternatives, including lifestyle programmes, dietary approaches, or referral to other specialists. Weight management is individual — your GP can help you find the approach that suits your health and circumstances best.
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.