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
Five Month Weight Loss: Realistic Goals and Timelines
Losing weight over five months is a realistic and sustainable timeframe for many UK adults. With consistent effort through diet, physical activity, and potentially prescription weight loss medication, most people can achieve meaningful results. The NHS recommends losing 0.5–1 kg per week for sustainable weight management, which means five months could result in weight loss of approximately 10–20 kg depending on your starting point and approach. Individual results vary significantly, and your GP can provide personalised guidance based on your health and circumstances.
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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.
What You Can Realistically Achieve in Five Months
Over a five-month period (approximately 20–21 weeks), following NHS weight loss guidance, you might expect to lose between 10 and 20 kg (approximately 1.5–3 stone) if you maintain consistent lifestyle changes. This assumes a calorie deficit of around 500 kcal per day, which is sustainable and doesn't require extreme restriction.
- 0.5 kg/week: Approximately 10–10.5 kg over five months
- 0.75 kg/week: Approximately 15–15.75 kg over five months
- 1 kg/week: Approximately 20–21 kg over five months
These figures are estimates — actual weight loss depends on your starting weight, age, metabolism, dietary adherence, and activity level. Using our free BMI calculator, you can track where your weight falls now and set a realistic target for where you'd like to be. Even a 5–10% reduction in body weight can deliver significant health benefits including improved blood sugar control, lower blood pressure, and reduced joint strain.
Clinically BackedWeight Loss
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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.
Five Month Weight Loss with Prescription Medication
If lifestyle changes alone aren't sufficient, GLP-1 weight loss medications (such as Wegovy or Mounjaro) may support your goals over five months. In clinical trials, prescription weight loss medication helped participants lose an average of 15–21% of their body weight over approximately 68 weeks — meaning five months could show noticeable progress alongside diet and exercise.
These are prescription-only medicines requiring assessment by a prescriber to confirm eligibility. For NHS weight management UK access, ask your GP about tier 3 specialist weight management services. For faster private access, you can seek an online clinical assessment from a UK-licensed prescriber. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses. Remember: medication supports weight loss but works best combined with reduced-calorie diet and increased physical activity.
- 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.
Is losing weight in five months realistic?
Yes — following NHS guidance of 0.5–1 kg per week, five months could result in 10–20 kg weight loss. This is a sustainable and realistic timeframe for most people who combine calorie reduction with physical activity.
What if I want faster weight loss in five months?
Faster loss (1.5+ kg/week) is possible with medical support but carries higher risks of muscle loss. Prescription weight loss medications may accelerate results, but ask your GP about safe options first.
Can I use slimming injections over five months?
Wegovy and Mounjaro are prescription-only weight loss injections that typically show effects within weeks. Five months allows time for dose escalation and meaningful weight loss, though individual results vary significantly.
How do I track progress over five months?
Use our free progress tracker to log weight weekly. Also monitor how clothes fit, energy levels, and health markers like blood pressure. Waist measurement can be more meaningful than weight alone for body composition changes.
What's the best approach for five month weight loss?
Combine a calorie deficit (approximately 500 kcal/day), increased physical activity, and consistency. Use our BMI calculator to set a realistic five-month target. Consider speaking with your GP about whether prescription medication or specialist support might help your specific situation.
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.