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 Timeline — UK Prescription Options
Postpartum weight loss happens gradually, and most women naturally lose weight in the months after birth. However, some find that excess weight remains despite diet and exercise. If you're struggling with postpartum weight management in the UK, prescription weight management options may be available after medical clearance. This guide covers the timeline, eligibility for treatment, and how to discuss options with your GP.
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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 Prescription Weight Loss Options After Pregnancy
Once you've been medically cleared by your GP (usually 6 weeks after birth, or 12 weeks if breastfeeding), prescription weight management medications may be available if you meet eligibility criteria. Three GLP-1 medications are licensed in the UK for weight management:
- Mounjaro (tirzepatide) — once-weekly injection, dual GIP and GLP-1 agonist. Clinical trials showed average weight loss of 15–21% body weight alongside diet and exercise changes.
- Wegovy (semaglutide) — once-weekly injection, GLP-1 agonist. Average weight loss around 15% body weight in clinical trials.
- Saxenda (liraglutide) — daily injection, GLP-1 agonist. Available but less commonly prescribed than weekly alternatives.
You must have a BMI of 30 or above, or 27 or above with weight-related health conditions such as high blood pressure or type 2 diabetes. Individual results vary and medications work best alongside reduced-calorie diet and increased physical activity. A prescriber will assess whether treatment is suitable for your individual circumstances.
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 Start
NHS access: Request a referral to your local tier 3 specialist weight management service from your GP. NHS availability varies significantly by region, and waiting lists can be long in some areas. Not all ICBs (integrated care boards) fund all medications equally.
Private access: Online consultations with UK-licensed prescribers are available without NHS referral. A clinical assessment determines eligibility; if approved, medication is dispensed by a GPhC-registered pharmacy. Costs vary by dose and provider.
Begin the conversation with your GP at your postpartum check-up. Use our free BMI calculator to check your current BMI before your appointment — this helps your GP assess eligibility. Many women find that combining medication with realistic lifestyle changes and our free progress tracker helps maintain motivation and consistency over time.
- 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.
When can I start prescription weight loss medication after giving birth?
Most GPs recommend waiting until your postpartum check-up (6 weeks, or 12 weeks if breastfeeding) before considering any medication. Breastfeeding and some medications are not compatible — always discuss this with your GP. Weight loss medication is not recommended while breastfeeding. Once cleared medically, eligibility then depends on your BMI and any weight-related health conditions.
Do weight loss injections work after pregnancy weight?
Clinical trials show GLP-1 and GIP/GLP-1 medications help support weight loss alongside diet and exercise. Individual results vary significantly. Some women see 15–clinically studied weight loss over time, though results depend on adherence, diet, exercise, and individual metabolism. Medication is most effective as part of a comprehensive approach, not as a standalone solution.
Will I still lose weight naturally while breastfeeding?
Many women lose weight naturally in the first 6 months postpartum, especially while breastfeeding — breastfeeding requires extra calories. However, this weight loss plateaus for some around 6 months postpartum. If you're breastfeeding and wish to lose weight, prescription medication is not recommended. Discuss safe diet and exercise options with your GP or a registered dietitian.
How long does postpartum weight loss usually take?
Most women lose 50–60% of pregnancy weight in the first month. An additional 10% typically comes off over the following 3–6 months as fluid decreases and fitness improves. For remaining weight, a calorie deficit of around 500 kcal per day supports loss of approximately 0.5 kg per week. Prescription weight loss medication may help if you meet eligibility criteria and have been medically cleared.
Can I get weight loss medication on the NHS after pregnancy?
Yes, if eligible. You must have a BMI of 30 or above, or 27 or above with weight-related health conditions. Request a referral from your GP to tier 3 specialist weight management services. NHS access varies by region and waiting times can be lengthy. Private options are available through UK-licensed prescribers if you prefer faster access after clinical assessment.
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.