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
Weight Loss After Birth: Safe, Healthy Approaches for UK Mothers
Losing weight after pregnancy is a common concern for UK mothers, but it's important to approach postpartum weight loss safely and gradually. Your body has undergone significant changes during pregnancy, and recovery takes time. The NHS recommends waiting at least 6 weeks after birth (or 3 months if you're breastfeeding) before focusing on active weight loss. This guide covers safe timelines, realistic expectations, and when prescription weight management support might be appropriate as part of longer-term health planning.
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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.
Safe Postpartum Weight Loss Timeline and Expectations
Most women naturally lose approximately 5–6 kg within the first two weeks after birth through fluid loss and the weight of the baby, placenta, and amniotic fluid. The remaining weight typically takes several months to a year to shift naturally.
The NHS recommends:
- Wait at least 6 weeks after vaginal birth before starting structured weight loss (12 weeks after caesarean section)
- If breastfeeding, wait until at least 3 months postpartum before active dieting — milk supply needs adequate nutrition
- Aim for gradual weight loss of 0.5–1 kg per week once you begin
- Eat regular, balanced meals — skipping meals reduces milk production and energy levels
- Stay hydrated — especially important if breastfeeding
- Avoid rapid or very low-calorie diets — these are unsafe postpartum and can affect breast milk quality
Your GP can assess your individual recovery and advise when it's safe to begin weight management. Use our free BMI calculator to understand your current weight status and healthy weight range for your height.
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.
Physical Activity, Nutrition, and When to Seek Professional Support
Gentle activity like walking can usually resume within a few weeks, but exercise intensity should increase gradually under NHS guidance. Pelvic floor exercises are especially important before returning to higher-impact activity.
For longer-term weight management in the UK, if you're overweight or obese (BMI 25 or above) and struggling with postpartum weight loss after 12 months, your GP can discuss options including structured diet programmes, referral to NHS weight management services, or — if eligible — prescription weight loss treatment such as GLP-1 medications like Wegovy or Mounjaro. These are only considered after lifestyle support and require a clinical assessment. Our free GLP-1 weight loss calculator can help you understand potential outcomes if medication becomes relevant later. Track your postpartum recovery with our progress tracker to monitor steady, sustainable progress.
- 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 trying to lose weight after giving birth?
The NHS recommends waiting at least 6 weeks after vaginal birth (12 weeks after caesarean) before active weight loss. If breastfeeding, wait until 3 months postpartum. Your GP can advise on your individual recovery timeline and safety.
Is it safe to diet while breastfeeding?
Severe calorie restriction is not recommended while breastfeeding — it can reduce milk supply and nutrient quality. Gentle, balanced eating and gradual weight loss (0.5–1 kg per week) is safe. Always consult your GP before starting any diet while nursing.
How much weight should I expect to lose naturally after birth?
Most mothers lose 5–6 kg in the first two weeks through fluid loss and delivery of the baby and placenta. Remaining pregnancy weight typically takes 6–12 months to shift naturally through normal activity and balanced eating.
What if I'm still overweight a year after giving birth?
If you're overweight or obese and weight loss has plateaued, speak to your GP. They can discuss structured weight management programmes through NHS services, or assess whether prescription weight loss medication might be appropriate alongside lifestyle changes.
Are weight loss injections like Wegovy safe after pregnancy?
Wegovy and Mounjaro are prescription-only medications. They are not recommended during pregnancy or breastfeeding. If you're interested in prescription weight management after you've finished breastfeeding, your GP or a licensed prescriber can assess your eligibility and individual health circumstances.
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.