The UK's most complete GLP-1 guide
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- 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 for PCOS: What You Need to Know
Polycystic ovary syndrome (PCOS) often makes weight management difficult, and many people with PCOS struggle to lose weight despite lifestyle changes. Mounjaro (tirzepatide) is a prescription-only injection that may help support weight loss in adults with PCOS by regulating appetite and food cravings. This guide explains how Mounjaro works for PCOS, UK eligibility criteria, and what the evidence shows about its potential benefits alongside your GP's support.
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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.
How Mounjaro Works for PCOS Weight Management
Mounjaro is a dual GIP and GLP-1 receptor agonist — meaning it activates two natural hormone pathways in your body that regulate appetite, blood sugar, and metabolism. For people with PCOS, this dual mechanism may offer particular benefits:
- Reduces appetite and food cravings, making it easier to eat fewer calories
- Helps regulate blood sugar levels — important for PCOS-related insulin resistance
- Slows gastric emptying, so you feel fuller after smaller meals
- May improve insulin sensitivity, addressing one of the root causes of PCOS-related weight gain
Clinical trials showed that adults on Mounjaro lost an average of 15–21% of their body weight over 72 weeks, though individual results vary significantly. For PCOS specifically, the weight loss effect is often combined with improved metabolic markers like fasting insulin and blood sugar levels. Mounjaro is given as a once-weekly KwikPen injection, with doses starting at 2.5 mg and titrating up to a maximum of 15 mg per week.
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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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PCOS, Weight, and Mounjaro Eligibility in the UK
In the UK, Mounjaro may be prescribed for adults with PCOS who meet weight management eligibility criteria: BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions. PCOS itself counts as a metabolic condition that increases eligibility. Access is through NHS specialist tier 3 weight management services (typically via GP referral) or through private online prescribing with a UK-licensed prescriber following a clinical assessment.
Your GP or prescriber will assess whether Mounjaro is suitable for your PCOS and overall health. Use our free BMI calculator above to check your starting point, and our GLP-1 weight loss calculator to estimate potential weight loss at different doses. Most importantly, Mounjaro works best alongside dietary changes and increased physical activity — it is not a replacement for lifestyle changes.
PCOS causes insulin resistance in up to 70% of people, leading to weight gain that is often resistant to diet and exercise alone. Mounjaro's ability to improve insulin sensitivity may address this underlying problem. However, not everyone with PCOS will be suitable for Mounjaro — pregnancy, breastfeeding, severe gastroparesis, or allergies to tirzepatide are contraindications. Women of childbearing age should use reliable contraception during treatment and for 4 weeks after stopping, as Mounjaro may reduce oral contraceptive absorption. Always discuss PCOS-specific concerns with your GP or prescriber before starting.
- 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 Mounjaro help with PCOS weight gain?
Yes, Mounjaro may help by addressing insulin resistance — a key driver of PCOS-related weight gain. Clinical evidence shows it supports weight loss in people with metabolic conditions, though results vary. Your GP can assess whether it is suitable for your specific PCOS presentation.
Is Mounjaro available on the NHS for PCOS?
Mounjaro is available through NHS specialist weight management services for eligible adults with PCOS and a BMI of 30 or above (or 27+ with comorbidities). Access varies by region and waiting lists can be long. Private prescribing is also available through UK-licensed online providers.
Will Mounjaro improve my PCOS symptoms beyond weight loss?
Some people experience improvements in insulin resistance, blood sugar control, and menstrual regularity as a secondary benefit of weight loss. However, Mounjaro is not a PCOS treatment — it is a weight management medication. Your GP may recommend additional PCOS-specific support.
What is the difference between Mounjaro and Wegovy for PCOS?
Mounjaro is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1-only agonist. Both may help with PCOS-related weight gain. Mounjaro may have an edge for insulin resistance, but Wegovy is also effective. Your prescriber will advise which suits you.
Can I take Mounjaro if I want to conceive with PCOS?
Mounjaro should be stopped if you are planning to conceive, as it is not recommended during pregnancy. Weight loss before conception can improve PCOS fertility outcomes. Discuss fertility plans with your GP before starting any weight loss medication.
Ready to take control of your weight loss journey?
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