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 See a Weight Loss Doctor in the UK
If you're looking for professional weight management support in the UK, you can access help through your GP or specialist weight loss services. The NHS provides a structured weight management pathway, whilst private options are also available. A weight loss doctor can assess your health, discuss prescription weight loss medication (such as GLP-1 injections), and help you develop a sustainable plan. Whether you want to explore medication options or lifestyle changes, understanding how to access these services is the first step towards managing your weight effectively.
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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.
NHS Weight Loss Services and Your GP
Your first port of call for weight management UK support is usually your GP. They can:
- Assess your overall health and BMI using the standard NHS classifications
- Identify weight-related health conditions like type 2 diabetes or high blood pressure
- Refer you to NHS weight loss programmes or tier 3 specialist services
- Discuss whether prescription weight loss medication might be appropriate
The NHS follows a tiered approach: tier 1 (self-help and digital tools), tier 2 (primary care interventions), tier 3 (specialist multidisciplinary services where medication is prescribed), and tier 4 (bariatric surgery). Access to specialist services varies significantly by region, and waiting lists can be lengthy. However, NHS weight loss medication NHS access is now available in many areas through specialist services, including prescription GLP-1 injections like Wegovy (semaglutide).
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.
Private Weight Loss Doctors and Online Options
If you prefer not to wait for NHS services, prescription weight loss UK is available through private online consultations. A UK-licensed prescriber can assess your eligibility during an online appointment, and if appropriate, issue a prescription for medications like Mounjaro or Wegovy. These are then dispensed by a GPhC-registered pharmacy. Private options typically cost £129–£320 per month depending on dose, though you avoid NHS waiting lists. Many people use our free BMI calculator and GLP-1 weight loss calculator before their appointment to understand their current health metrics and potential outcomes with medication.
Whichever route you choose, a qualified weight loss doctor will assess several factors: your BMI, whether you have weight-related health conditions, your medical history, and your motivation for weight management. Lose weight UK guidance emphasizes that sustainable weight loss combines medication (if prescribed) with dietary changes and increased physical activity. A weight loss doctor can also recommend diet styles, exercise plans, and monitor your progress. Using our free progress tracker alongside professional support helps you stay accountable and celebrate milestones throughout your weight loss journey.
- 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 BMI do I need to be prescribed weight loss medication by a doctor?
Generally, you may be eligible for prescription weight loss medication if your BMI is 30 or above, or 27–29.9 with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply. A doctor will assess your individual circumstances during consultation.
What's the difference between NHS and private weight loss doctors?
NHS weight loss services are free but may involve waiting lists of several months to years depending on your region. Private weight loss doctors offer faster appointments and prescription medication without NHS referral, typically costing £100–£300 per month. Both routes require a clinical assessment before prescribing medication. Choose based on your budget and timeframe preferences.
Can a GP prescribe weight loss injections like Wegovy or Mounjaro?
Some GPs can prescribe these medications, but most are prescribed through NHS specialist tier 3 services or private online prescribers. If your GP cannot prescribe, they should refer you to a specialist weight management service. Private online doctors can also prescribe following a clinical consultation. Always ensure the prescriber is UK-licensed and registered.
What happens during a weight loss doctor appointment?
A weight loss doctor will review your medical history, measure your BMI, discuss your weight-related health conditions, and understand your weight loss goals. They'll explain medication options if appropriate, discuss lifestyle changes, and outline expected outcomes. You may be offered prescription medication (such as GLP-1 injections), referral to dietitians, or behaviour change support depending on your circumstances.
Is weight loss medication prescribed alone or alongside diet and exercise?
Weight loss medications work best alongside reduced-calorie diet and increased physical activity. Clinical trials show medications like Wegovy and Mounjaro help participants lose an average of 15–21% body weight, but individual results vary significantly. A good weight loss doctor will emphasize that medication supports lifestyle changes rather than replacing them, and will help you develop a comprehensive plan.
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.