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
Can Acid Reflux Cause Weight Loss?
Acid reflux (gastro-oesophageal reflux disease, or GORD) can sometimes contribute to weight loss, though usually indirectly. When reflux is severe, it may reduce appetite, cause discomfort when eating, or lead people to avoid certain foods — all of which can result in reduced calorie intake. Interestingly, weight management UK medications like GLP-1 injections can also trigger or worsen acid reflux as a side effect. This guide explains the connection between acid reflux and weight loss, what causes it, and when you should speak to your GP.
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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.
How Acid Reflux Affects Weight
Acid reflux doesn't directly cause weight loss in the way that, say, an infection might. Instead, it can create conditions that lead to reduced eating and weight loss indirectly:
- Reduced appetite: Chronic reflux discomfort can suppress hunger signals and make eating feel unappealing.
- Avoidance of trigger foods: People with GORD often avoid spicy, fatty, acidic, or large meals — naturally reducing calorie intake.
- Nausea and discomfort: Persistent nausea or chest discomfort makes eating less enjoyable and smaller portions more likely.
- Sleep disruption: Reflux worsens when lying down, so poor sleep can affect hunger hormones and metabolism.
The NHS recommends that if you're experiencing unintentional weight loss alongside reflux, you should speak to your GP to rule out underlying health issues. Unintentional weight loss can sometimes signal conditions that need investigation.
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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.
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Acid Reflux as a Side Effect of Weight Loss Medications
A common but important side effect: GLP-1 weight loss injections like Wegovy can trigger or worsen acid reflux in some users. Wegovy works by slowing how quickly food leaves your stomach (gastric emptying), which can increase reflux risk. Clinical trials and user reports show that indigestion and acid reflux are among the most commonly reported side effects of GLP-1 medication. If you're considering prescription weight loss UK treatment, discuss any history of GORD with your prescriber — they may adjust your approach or recommend gastroprotective medication. Use our free GLP-1 weight loss calculator to explore options, and always mention reflux symptoms to your clinical assessor.
- 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.
Is unintentional weight loss from acid reflux normal?
No — unintentional weight loss deserves investigation. While mild reflux might reduce appetite temporarily, significant unexplained weight loss can indicate other conditions like ulcers, Barrett's oesophagus, or malabsorption. Contact your GP if you're losing weight without trying, especially alongside reflux symptoms.
Can treating acid reflux help me gain weight back?
Yes, often. Once reflux is well-managed with medication (PPIs or H2 blockers) or lifestyle changes, appetite typically improves and normal eating patterns return. This can lead to gradual weight regain if desired. Your GP can monitor your progress.
Will Wegovy or Mounjaro make my acid reflux worse?
Both GLP-1 and GIP/GLP-1 medications can trigger or worsen acid reflux in some people, particularly in the first few weeks or at higher doses. If you have existing GORD, discuss this with your prescriber before starting — they may recommend additional management or dose adjustments.
What's the difference between indigestion and acid reflux?
Indigestion (dyspepsia) is discomfort in the upper stomach, often after eating. Acid reflux (GORD) occurs when stomach acid moves up into the oesophagus, causing heartburn and regurgitation. Both can be side effects of weight loss medication, but they're distinct conditions.
Should I stop weight loss injections if I get reflux?
Don't stop on your own — always speak to your prescriber. Many people manage reflux alongside GLP-1 medication using PPIs or H2 blockers, or by adjusting dose timing. Your prescriber can find a plan that works for you.
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.