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 with SLE — NHS Guidance for UK Adults
Systemic lupus erythematosus (SLE) can complicate weight management due to inflammation, medication side effects, and fatigue. If you have SLE and need to lose weight, it's essential to work closely with your GP and specialist team to develop a safe, sustainable plan. Weight loss can help reduce joint stress and improve overall health, but requires careful medical supervision given the complexity of SLE management and potential medication interactions.
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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.
How SLE Affects Weight Management
SLE can impact weight in several ways. Corticosteroid medications, commonly prescribed to manage SLE symptoms, can increase appetite and promote fluid retention, making weight loss challenging. Inflammation associated with SLE may reduce energy levels and make regular physical activity difficult. Additionally, fatigue is a hallmark of SLE and can limit exercise capacity.
- Corticosteroids (like prednisolone) may increase appetite and fluid retention
- SLE-related fatigue can reduce your ability to exercise consistently
- Inflammation may affect metabolism and energy balance
- Some immunosuppressive medications may contribute to weight gain
Despite these challenges, sustainable weight loss is possible with the right support. Even modest weight loss of 5–10% can reduce stress on joints and improve cardiovascular health, which is particularly important for SLE patients who have elevated heart disease risk.
Clinically BackedWeight Loss
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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.
Safe Weight Loss Approaches for SLE
Your GP and rheumatology team should be involved in any weight loss plan. NHS weight management guidance recommends a gradual approach: aim to lose 0.5–1 kg per week through a combination of modest dietary changes and gentle physical activity suited to your energy levels.
- Work with your GP before starting any diet or exercise programme
- Consider referral to NHS Tier 2 or Tier 3 weight management services for specialist support
- Discuss medication interactions — some weight loss medications may not be suitable with SLE treatments
- Include low-impact activities like swimming or gentle walking that won't aggravate SLE symptoms
- Monitor your symptoms closely and adjust activity as needed on high-fatigue days
Prescription weight loss medication may be an option for some SLE patients, but requires careful assessment by your prescriber alongside your rheumatology team to ensure no interactions with immunosuppressive therapy.
- 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 Wegovy or Mounjaro if I have SLE?
Prescription weight loss medications like Wegovy (semaglutide) or Mounjaro (tirzepatide) may be considered for weight management in SLE patients, but this requires careful assessment. You must inform your prescriber and rheumatology team of your SLE diagnosis and all current medications. There may be interactions with immunosuppressive treatments. Never start any new medication without discussing with both your GP and specialist.
Does SLE make weight loss harder?
Yes, SLE can make weight loss more challenging due to corticosteroid side effects, fatigue, inflammation, and reduced exercise tolerance. However, sustainable weight loss is still achievable with medical support, a realistic plan, and flexibility. Working with your GP and specialist team increases your chances of success while managing your SLE safely.
What exercise is safe with SLE for weight loss?
Low-impact activities are generally best: swimming, walking, gentle yoga, or water aerobics. These minimise joint stress while building fitness. Start gradually and increase intensity slowly. Listen to your body — on high-fatigue days, gentle movement is acceptable. Always discuss your exercise plan with your GP or rheumatology team first.
Should I use the MyWeightCheck BMI calculator if I have SLE?
Yes, our free BMI calculator can help you track your weight status and set realistic goals. Remember that BMI is a screening tool with limitations — it doesn't account for muscle mass or inflammation. Use it alongside professional medical guidance from your GP for a complete picture of your health.
How much weight should I lose with SLE?
The NHS recommends losing 0.5–1 kg per week for sustainable results. Even 5–10% of your current body weight can have significant health benefits for SLE patients, including reduced joint pain and improved cardiovascular health. Aim for gradual, consistent loss rather than rapid changes. Your GP can help set personalised targets based on your health profile.
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.