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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Acid Reflux and Weight Loss: What UK Adults Need to Know
Acid reflux and weight loss are often connected — excess weight can worsen reflux symptoms, and some weight loss medications may cause reflux as a side effect. If you're managing both conditions, understanding your options is important. The UK offers several prescription weight management solutions for eligible adults, alongside lifestyle changes and NHS support. This guide explains how acid reflux relates to weight, which medications are available, and how to discuss your options with your GP.
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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.
UK-Licensed Weight Loss Medication Options
Three prescription-only weight management medications are currently licensed in the UK for adults with a BMI of 30 or above, or 27 or above with weight-related health conditions:
- Mounjaro (tirzepatide): A once-weekly dual GIP and GLP-1 receptor agonist injection. Typical clinical trial results showed average weight loss of 15–21% of body weight alongside a reduced-calorie diet and increased physical activity. Common side effects include nausea, diarrhoea, and stomach discomfort — including acid reflux in some users.
- Wegovy (semaglutide): A once-weekly GLP-1 receptor agonist injection. Clinical trial data showed average weight loss of approximately 15% of body weight. Like Mounjaro, gastrointestinal side effects including acid reflux can occur, especially during dose escalation.
- Saxenda (liraglutide): A once-daily GLP-1 injection. Similar side effect profile to Wegovy.
All three medications require a clinical assessment and prescription. They are not available over the counter and work best alongside lifestyle changes. Individual results vary significantly. If you have existing acid reflux, your prescriber will assess whether these medications are suitable for you.
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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.
NHS vs Private Access and Next Steps
Accessing weight loss medication in the UK:
- NHS route: Through specialist tier 3 weight management services following a GP referral. Availability and waiting times vary significantly by region. Your GP can advise if you meet local NHS eligibility criteria.
- Private route: Through GPhC-registered online prescribing services following a clinical consultation. Available without an NHS referral, though costs apply.
Before starting any weight loss medication, discuss your acid reflux history with your prescriber. They will assess whether medication is appropriate for you and may recommend additional reflux management — such as dietary adjustments, timing of meals, or antacids — alongside weight loss treatment. Use our free BMI calculator and GLP-1 weight loss calculator to understand your baseline and projected outcomes, then have a detailed conversation with your GP about which approach suits you best.
- 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 weight loss medication cause or worsen acid reflux?
Yes, GLP-1 and GIP/GLP-1 medications can cause acid reflux or indigestion as a common side effect, particularly during the initial weeks or when doses are increased. This typically improves over time. If you have existing acid reflux, inform your prescriber — they can monitor you and suggest management strategies.
Does losing weight help with acid reflux symptoms?
Yes, evidence shows that losing even 5–10% of body weight can significantly reduce acid reflux symptoms in overweight or obese individuals. Weight loss reduces pressure on the stomach and improves digestive function, making it an important part of reflux management alongside lifestyle changes.
How do I know if I'm eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27 or above with weight-related health conditions (including acid reflux complications). Eligibility criteria vary by region. Your GP can assess your individual case and refer you to specialist services if appropriate.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections for weight loss. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro may produce slightly greater average weight loss. Both have similar side effect profiles including potential reflux. A prescriber will recommend the most suitable option for your health profile.
Should I stop taking acid reflux medication when I start weight loss injections?
No — continue taking your current acid reflux medications unless your GP advises otherwise. Weight loss medication and reflux treatment work independently. As you lose weight, your GP may review your reflux medication dose, but this is a separate decision based on your symptoms and digestive health.
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.