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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Postpartum Weight Loss Plan — Prescription Medication Options in the UK
Losing weight after pregnancy can feel challenging, and for many women in the UK, prescription weight management medication may be an option worth exploring alongside lifestyle changes. If you're struggling with postpartum weight loss, understanding what's available through the NHS and privately can help you make an informed decision. This guide covers the prescription options, eligibility criteria, and how to get started with a conversation with your GP about whether medication might support your journey.
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Calculate Your BMI Instantly
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 Prescription Weight Loss Options for Postpartum Weight Management
Three prescription medications are currently licensed in the UK for weight management and may be available to eligible postpartum women: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 and GIP/GLP-1 receptor agonist medications that work by helping regulate appetite and supporting you to feel fuller after meals. Clinical trials have shown these medications, when combined with reduced-calorie diet and increased physical activity, may help participants lose an average of 15–21% of their body weight — though individual results vary significantly. Mounjaro and Wegovy are once-weekly injections, whilst Saxenda is a daily injection. All three are prescription-only medicines and require a clinical assessment before being prescribed. Eligibility is assessed on an individual basis, taking into account your BMI, health history, and overall circumstances.
Use our free GLP-1 weight loss calculator above to explore potential weight loss ranges at different doses if you're considering medication, and our BMI calculator to check where you currently fall on the NHS weight categories.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 vs Private Access — How to Find Out If You're Eligible
NHS route: Ask your GP for a referral to a tier 3 specialist weight management service. Eligibility typically includes women with a BMI of 30 or above, or 27 or above with weight-related health conditions (such as prediabetes, high blood pressure, or sleep apnoea). NHS access varies significantly by region — some areas have lengthy waiting lists. Private route: You can access prescription weight management through a GPhC-registered online pharmacy following an online clinical assessment with a UK-licensed prescriber. This does not require an NHS referral and is typically faster, though there is a cost. Either way, a healthcare professional will assess whether medication is suitable for you based on your individual health, medications, and circumstances. Postpartum considerations (such as breastfeeding status) will also be discussed.
- 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 take weight loss medication while breastfeeding?
No. GLP-1 and GIP/GLP-1 medications are not recommended during breastfeeding. If you're breastfeeding, discuss alternatives with your GP or healthcare provider. If you've stopped breastfeeding or plan to, medication may become an option — your prescriber will assess this individually.
How soon after pregnancy can I start prescription weight loss medication?
There's no fixed timeline — it depends on your individual recovery, whether you're breastfeeding, and your overall health. Discuss with your GP at your postpartum check-up. Many women begin exploring options 6–12 weeks postpartum, but this is individual.
Will weight loss medication work without diet and exercise changes?
No. Prescription medications are most effective when combined with a reduced-calorie diet and increased physical activity. Medication supports these lifestyle changes — it doesn't replace them. Your GP or prescriber will discuss realistic expectations.
What if I don't meet NHS eligibility criteria?
You can still explore private prescription options through online prescribing services. A licensed prescriber will assess whether medication is clinically appropriate for you based on your individual circumstances, not just BMI.
How can I track my postpartum weight loss progress?
Use our free progress tracker on this page to log your weight over time. Combined with regular BMI checks using our BMI calculator, this helps you monitor your journey and see progress beyond the scales.
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.