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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Mounjaro and Dry Mouth — What You Need to Know
Dry mouth is a recognised side effect of Mounjaro (tirzepatide), though it's not listed as one of the most common effects. If you're taking this prescription weight management injection in the UK, understanding why dry mouth occurs and how to manage it can help you stay comfortable during treatment. This guide explains the causes, duration, and practical strategies to minimise the symptom.
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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.
Why Does Mounjaro Cause Dry Mouth?
Dry mouth with Mounjaro occurs due to several mechanisms related to how tirzepatide works in your body. The medication activates GLP-1 and GIP receptors, which affect how your digestive system functions. This can slow gastric emptying and reduce overall fluid intake if you're feeling fuller more quickly. Additionally, GLP-1 receptor activation may affect salivary gland function directly, reducing saliva production. Some people experience nausea or changes in appetite that lead to reduced eating and drinking, indirectly contributing to dry mouth. The effect is usually mild and tends to improve as your body adjusts to the medication over the first few weeks of treatment or dose increases. If dry mouth persists beyond 4–6 weeks at a stable dose, inform your GP or the NHS specialist prescribing your Mounjaro, as there may be other contributing factors.
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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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Managing Dry Mouth While Taking Mounjaro
Several practical strategies can help manage dry mouth during Mounjaro treatment. Stay hydrated — drink water regularly throughout the day, even if you don't feel thirsty; aim for at least 6–8 glasses daily. Sugar-free products like sugar-free gum, lozenges, or mouthwash can stimulate saliva production without adding calories. Avoid triggers — limit caffeine, alcohol, and very salty foods, as these can worsen dryness. Use a humidifier in your bedroom at night. If dry mouth is severe or doesn't improve after 6 weeks, speak to your GP or the NHS tier 3 specialist managing your weight loss, as they may adjust your dose or suggest prescription saliva substitutes. Track how the symptom changes as you progress through dose titration — most people find it resolves naturally.
- 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 dry mouth common with Mounjaro in the UK?
Dry mouth is not listed as a very common side effect of Mounjaro. It affects some people but is less frequent than nausea, diarrhoea, or constipation. Individual experience varies. If you develop dry mouth, inform your GP or NHS prescriber.
How long does Mounjaro dry mouth last?
Dry mouth typically improves within 2–6 weeks as your body adjusts to the medication. It often resolves after dose titration stabilises. If it persists beyond 6 weeks at a constant dose, seek advice from your prescriber about management strategies or potential dose adjustment.
Can I use sugar-free mints or gum to help with Mounjaro dry mouth?
Yes, sugar-free gum and mints can help stimulate saliva production and are safe to use during Mounjaro treatment. They won't interfere with the medication's effectiveness and may help manage discomfort without adding calories.
Should I tell my GP about dry mouth while taking Mounjaro?
Yes, inform your GP or the NHS specialist prescribing your Mounjaro about any persistent side effects, including dry mouth lasting more than a few weeks. They can confirm it's medication-related and suggest management strategies or prescription saliva substitutes if needed.
Does dry mouth mean Mounjaro isn't working?
No. Dry mouth is a side effect unrelated to how well Mounjaro is helping you lose weight. Use our free GLP-1 weight loss calculator to track your progress independently, and discuss any side effects separately with your prescriber during follow-up appointments.
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