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
Does Omeprazole Cause Weight Loss?
Omeprazole is a common acid-reflux medication used by millions in the UK, but it's not designed for weight loss. In fact, some people may experience modest weight gain while taking it. If you're looking for evidence-based weight management support, the NHS and private options offer prescription medications specifically approved for weight loss in UK adults—these are very different from omeprazole and are prescribed only after clinical assessment by a qualified healthcare professional.
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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.
How Omeprazole Affects Weight
Omeprazole is a proton pump inhibitor (PPI) used to treat acid reflux, heartburn, and stomach ulcers. It works by reducing stomach acid production, not by affecting appetite or metabolism. Weight loss is not an intended or common effect of omeprazole.
Some people taking omeprazole may experience mild weight changes—either gain or loss—but this is typically due to:
- Relief from painful reflux, allowing more normal eating patterns
- Individual metabolic variation
- Changes in diet or lifestyle during treatment
- Other underlying health conditions
Omeprazole is not a weight loss medication and should never be used for this purpose. If you're concerned about weight management, speak to your GP about evidence-based options tailored to your individual health needs.
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.
Prescription Weight Loss Options in the UK
For adults who wish to lose weight, the NHS and private healthcare both offer prescription weight loss medications that are clinically proven to help with weight management uk outcomes. These include Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide)—all GLP-1 receptor agonist medications licensed specifically for weight loss.
Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes or high blood pressure. Our GLP-1 weight loss calculator can help you explore potential outcomes, whilst our BMI calculator shows your current weight category. Access through NHS weight loss services or private online prescribing following clinical assessment.
- 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 omeprazole help me lose weight?
No. Omeprazole is not a weight loss medication—it's used to treat acid reflux and stomach ulcers. Weight loss is not an intended effect. If you're interested in prescription weight management, speak to your GP about NHS-approved options like Mounjaro or Wegovy, which are licensed specifically for weight loss in eligible adults.
Could omeprazole cause weight loss as a side effect?
Whilst weight loss is not a common side effect of omeprazole, some people may experience weight changes during treatment. This is usually due to improved eating comfort after reflux relief, rather than the medication itself. Any significant weight changes should be discussed with your GP.
What are the NHS-approved weight loss medications in the UK?
Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide) are prescription weight loss medications licensed in the UK. They are GLP-1 receptor agonists that work by helping regulate appetite and supporting feeling fuller after meals. Eligibility is assessed individually by a prescriber.
How do I know if I'm eligible for prescription weight loss medication?
Generally, you may be eligible if your BMI is 30 or above, or 27 or above with weight-related health conditions. Use our free BMI calculator to check your current BMI, then discuss your individual situation with your GP or a private prescriber who can assess suitability based on your health.
What's the difference between omeprazole and actual weight loss medication?
Omeprazole treats stomach acid; it doesn't affect appetite or metabolism. Weight loss medications like Mounjaro and Wegovy are GLP-1 agonists designed specifically to regulate appetite and support weight management. Clinical trials show these can help people lose 15–21% of body weight on average—very different from omeprazole's purpose.
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.