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 Medication for Lupus in the UK
Living with lupus can make weight management challenging due to inflammation, medications, and fatigue. If you have lupus and need to lose weight, prescription weight loss medication may be an option. This guide explains UK-licensed treatments, how they work alongside lupus management, and how to discuss weight management with your GP in the context of your overall 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 Prescription Weight Loss Options for Lupus Patients
Three prescription medications are currently licensed in the UK for weight management and may be suitable for eligible adults with lupus: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These GLP-1 receptor agonist medications work by helping reduce appetite and supporting feeling fuller after smaller meals. For lupus patients specifically, weight management can be important because excess weight increases inflammation markers and may complicate lupus-related health conditions such as high blood pressure or joint stress.
- Mounjaro: Once-weekly injection, dual GIP and GLP-1 action, average weight loss 15–21% in clinical trials
- Wegovy: Once-weekly injection, GLP-1 only, average weight loss approximately 15% in clinical trials
- Saxenda: Once-daily injection, GLP-1 only, lower average weight loss but daily flexibility
All three are prescription-only and require a clinical assessment before being prescribed. Your GP will need to consider how these medications interact with your lupus medications and overall treatment plan.
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 Access and Private Options in the UK
In the UK, prescription weight loss medication is available through two routes. NHS access is through specialist tier 3 and tier 4 weight management services—typically requiring a GP referral and meeting specific BMI criteria (usually BMI of 30 or above, or 27–29.9 with weight-related health conditions). However, NHS availability varies significantly by region, and waiting lists can be lengthy. Private access is available through online prescribing services following a clinical assessment with a UK-licensed prescriber, without requiring an NHS referral. Your GP can advise you on both routes and help you understand what's available in your area. Discuss your lupus medications openly—your prescriber needs to assess any interactions before starting weight loss medication.
- 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 I take weight loss injections if I have lupus?
Weight loss medications may be suitable for some lupus patients, but it depends on your individual health situation and current lupus treatments. Some lupus medications may interact with GLP-1 injections. You must discuss this with your GP or rheumatologist before starting any weight loss medication. A prescriber will assess your eligibility based on your overall health, BMI, and medication interactions.
Will weight loss help my lupus symptoms?
Losing weight may help reduce inflammation and ease stress on joints, which can benefit some lupus symptoms. Excess weight increases inflammation markers, which may worsen lupus activity. However, weight loss is not a treatment for lupus itself. Always follow your rheumatologist's treatment plan and discuss weight management as part of your overall care strategy.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
Generally, you may be eligible if you have a BMI of 30 or above, or 25–29.9 with weight-related health conditions. However, lupus patients should first speak with their GP or rheumatologist about whether weight loss medication is appropriate given their specific lupus treatment plan. Your prescriber will conduct a full health assessment before offering treatment.
What's the difference between NHS and private weight loss medication in the UK?
NHS treatment is through specialist weight management services via GP referral, but availability varies by region and waiting lists can be long. Private treatment is available through online prescribing services following a clinical assessment, without requiring an NHS referral. Both require a prescription from a UK-licensed prescriber. Private costs typically range from £129–£320 per month depending on dose.
Can I use the GLP-1 calculator if I have lupus?
Our free GLP-1 weight loss calculator provides weight loss projections based on clinical trial data, but these are general estimates. If you have lupus, discuss your personalised weight loss goals with your GP or prescriber, as lupus-specific factors may affect your outcome. Use the calculator as a general guide, not as medical advice specific to your condition.
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.