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 Mounjaro Cause Yeast Infections?
Yeast infections are not listed as a common or very common side effect of Mounjaro (tirzepatide) in the UK product information or clinical trials. However, some people taking GLP-1 and GIP receptor agonist medications report fungal infections. This guide explains what the NHS says about Mounjaro side effects, when to seek help from your GP, and how to manage your health whilst taking this prescription-only weight loss injection.
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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.
What Does the NHS Say About Mounjaro Side Effects?
Mounjaro is a prescription-only GIP and GLP-1 receptor agonist approved by the MHRA for weight management in UK adults. In the SURMOUNT clinical trials, the most commonly reported side effects were nausea, diarrhoea, vomiting, and constipation — affecting gastrointestinal function rather than immune or reproductive health.
Yeast infections are not listed as a common side effect in the official UK prescribing information. However, some medical literature suggests that gradual weight management and changes in gut bacteria from GLP-1 medications may occasionally increase fungal infection risk in susceptible individuals. If you develop signs of a yeast infection whilst taking Mounjaro — such as itching, unusual discharge, or discomfort — contact your GP promptly.
- Mounjaro works via dual hormone pathways, affecting appetite and gastric emptying
- Gastrointestinal side effects are most common, not infections
- Individual responses vary — not everyone experiences side effects
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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.
When Should You Contact Your GP About Mounjaro?
Always inform your GP or prescriber if you develop any new symptoms whilst taking Mounjaro, including signs of infection. Your healthcare team needs to know about vaginal itching, unusual vaginal discharge, oral thrush (white patches in the mouth), or skin fungal infections.
Your GP can assess whether the symptom is related to Mounjaro or another cause, and recommend appropriate treatment. They can also advise whether to continue, pause, or adjust your Mounjaro dose if needed. If you're taking Mounjaro through NHS specialist weight management services or via a private prescription, both routes require ongoing clinical support — use these channels to report any concerns.
- 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 a yeast infection a known side effect of Mounjaro in the UK?
No. Yeast infections are not listed as a common or very common side effect in the UK product information or SURMOUNT trial data. The most frequent side effects affect the digestive system. However, any new symptoms should be reported to your GP for assessment.
Can GLP-1 medications like Mounjaro increase infection risk?
GLP-1 and GIP receptor agonists primarily affect appetite and blood sugar. Whilst yeast infections are uncommon, gradual weight management and changes in gut bacteria may theoretically increase risk in some individuals. This is not a common problem but warrants medical attention if it occurs.
What should I do if I develop symptoms of a yeast infection on Mounjaro?
Contact your GP immediately. Describe your symptoms clearly — they can determine the cause and recommend treatment. Do not stop taking Mounjaro without medical advice. Your prescriber needs to know about all new symptoms to manage your care safely.
Will my GP need to stop my Mounjaro if I get a yeast infection?
Not necessarily. Most yeast infections are treatable and do not require stopping Mounjaro. Your GP will assess the severity, recommend antifungal treatment, and advise on continuing your weight loss medication. Treatment decisions are individual.
How can I reduce the risk of yeast infections whilst on Mounjaro?
Maintain good hygiene, wear breathable clothing, avoid douches and scented products, and stay hydrated. If you have a history of recurrent yeast infections, inform your GP or prescriber before starting Mounjaro. Use our GLP-1 weight loss calculator to understand what Mounjaro may do, and consult your GP about personal risk factors.
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.