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 Reflux Cause Weight Loss?
Reflux does not directly cause weight loss — but unmanaged reflux can reduce appetite and food intake, which may lead to weight loss over time. More commonly in the UK, people experience reflux as a side effect of prescription weight loss medications like Wegovy (semaglutide) or Mounjaro (tirzepatide). If you're experiencing new or worsening reflux alongside weight loss, it's important to discuss this with your GP, as managing the reflux itself is often the priority.
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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.
Reflux and Weight Loss — What's the Connection?
Acid reflux (gastro-oesophageal reflux disease or GORD) does not directly cause weight loss in most cases. However, untreated reflux can indirectly contribute to weight changes by reducing your appetite or making eating uncomfortable, which may lead to lower calorie intake and gradual weight loss.
More commonly, people report reflux as a side effect of weight loss medication. Clinical trials of GLP-1 weight loss injections like Wegovy showed that reflux and indigestion are common side effects, affecting up to 1 in 10 people. Similarly, Mounjaro (tirzepatide) lists indigestion and acid reflux among very common side effects in some users.
If you develop reflux while using weight management medication, this is worth reporting to your prescriber — there are often practical steps to manage it, such as adjusting meal timing, portion sizes, or taking over-the-counter antacids.
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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.
Managing Reflux Alongside Weight Loss Treatment
If you're experiencing reflux during prescription weight loss medication, your GP or prescriber can help you manage both issues simultaneously. Practical strategies include eating smaller, more frequent meals; avoiding trigger foods like spicy or fatty foods; staying upright after eating; and taking antacids as needed.
Never stop taking your weight loss medication without speaking to your prescriber first. In many cases, reflux improves as your body adjusts to the medication, or it can be managed with simple lifestyle tweaks. Use the GLP-1 weight loss calculator on this page to understand what medication might be suitable for you, and always discuss any side effects openly with your GP to find the best approach for your individual weight management needs.
- 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 acid reflux actually cause weight loss?
Acid reflux does not directly cause weight loss in most people. However, severe untreated reflux may reduce appetite or make eating uncomfortable, leading to lower food intake and gradual weight loss. If you're experiencing unexplained weight loss alongside reflux, speak to your GP to rule out other underlying health issues.
Is reflux a common side effect of Wegovy or weight loss injections?
Yes. Clinical trials of Wegovy (semaglutide) showed that indigestion and acid reflux affect up to 1 in 10 users. Mounjaro lists reflux and indigestion as very common side effects. These often improve as your body adjusts, or can be managed with lifestyle changes and antacids.
What should I do if I develop reflux while taking prescription weight loss medication?
Contact your prescriber or GP immediately. Do not stop the medication without professional guidance. They can recommend practical strategies like smaller meals, trigger food avoidance, antacids, or dose adjustments to help manage reflux while continuing your weight loss treatment.
Does GLP-1 medication slow stomach emptying, and is that linked to reflux?
Yes. GLP-1 medications like Wegovy slow gastric emptying (how quickly food leaves your stomach), which supports weight loss but may increase reflux risk in some people. This effect often decreases over time. Your GP can advise on timing of meals and medication to minimise reflux symptoms.
Will reflux stop if I stop taking my weight loss injection?
Reflux may improve after stopping the medication, but this should only be done under GP guidance. In most cases, reflux can be managed while continuing treatment. Stopping medication without medical advice may mean losing the weight loss benefits you've achieved. Always discuss concerns with your prescriber first.
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.