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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Weight Loss Medication for PCOS in the UK
Polycystic ovary syndrome (PCOS) can make weight management significantly more challenging due to insulin resistance and hormonal imbalance. If you have PCOS and are struggling with weight gain, prescription weight loss medication may be an option worth discussing with your GP. Several evidence-based treatments are now available through the NHS and private prescribing in the UK, often used alongside lifestyle changes. This guide explains what's available, who is eligible, and how to explore whether prescription medication might help you manage your weight and PCOS-related health concerns.
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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.
UK-Licensed Weight Loss Medications for PCOS
Three prescription medications are currently licensed in the UK for weight management and may be considered for adults with PCOS who meet eligibility criteria. These are GLP-1 receptor agonists — medications that work by reducing appetite, slowing digestion, and improving blood sugar control, which is particularly relevant for PCOS-related insulin resistance.
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 agonist, injected once weekly. Average weight loss in clinical trials was approximately 15–21% of body weight over 72 weeks, alongside diet and exercise changes.
- Wegovy (semaglutide) — a GLP-1 agonist, once-weekly injection. Clinical trial data showed average weight loss of around 15% over 68 weeks.
- Saxenda (liraglutide) — a GLP-1 agonist, injected daily. Less commonly prescribed due to daily dosing, but evidence supports modest weight loss benefit.
Individual results vary significantly. These medications require a prescription and are only suitable if your GP or a specialist assesses you as clinically appropriate. Our GLP-1 weight loss calculator can help you estimate potential weight loss ranges at different doses if you're considering this option.
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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.
NHS Access vs Private Prescribing — Which Route Is Right for You?
NHS access: Weight loss medications are available through NHS specialist weight management services (tier 3). However, access varies significantly by region, and waiting lists can be lengthy. You'll need a referral from your GP to a specialist service, which will assess whether you're eligible based on your BMI, PCOS status, and other health factors. Use our BMI calculator to check where you fall on the NHS weight categories.
Private prescribing: These medications are also available through GPhC-registered online prescribing services following a clinical assessment. This route doesn't require an NHS referral and may offer faster access, though costs typically range from £130–£350 per month depending on dose.
Next step: Start by speaking with your GP. They can assess your individual situation, discuss whether prescription weight loss medication is appropriate for your PCOS, and guide you through either NHS referral or discuss private options.
- 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 I get weight loss medication on the NHS if I have PCOS?
Yes, potentially. PCOS-related weight gain is recognised as a health condition that may qualify you for NHS prescription weight loss treatment if your BMI meets criteria (usually 30 or above, or 27+ with comorbidities). However, NHS access varies by region and involves referral to a specialist weight management service. Your GP can advise on availability in your area and refer you if appropriate.
What's the difference between Mounjaro and Wegovy for PCOS weight loss?
Both are once-weekly injections and work through appetite regulation, but they use slightly different mechanisms. Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), while Wegovy (semaglutide) activates one (GLP-1). Clinical trial data suggests Mounjaro may produce marginally greater average weight loss, but individual responses vary. Your prescriber will recommend which is most suitable based on your health profile.
How quickly will I lose weight on these medications?
Weight loss is typically gradual and varies between individuals. Most people see modest changes in the first few weeks, with more significant loss over months. Average results from clinical trials suggest 0.5–1 kg per week sustained over several months when combined with reduced-calorie diet and physical activity. Results are not assured, and some people lose more or less than the average.
Are there any side effects I should know about?
Common side effects include nausea, diarrhoea, constipation, and stomach discomfort — often mild and improving over time as your body adjusts. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) or gallbladder problems. Your prescriber will discuss all risks before you start, and you should report any concerning symptoms to your GP.
Do I need to change my diet and exercise if I take weight loss medication?
Yes. Prescription weight loss medications work best alongside dietary changes and increased physical activity — they're not a replacement for lifestyle changes. The NHS recommends a moderate calorie deficit (around 500 kcal per day) combined with regular movement. Your prescriber can discuss realistic targets and connect you with diet and exercise support resources.
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.