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
Do Laxatives Help With Weight Loss?
Laxatives do not help with genuine, sustainable weight loss. While they may cause temporary water weight reduction, this is not fat loss and returns quickly once you stop using them. Many people turn to laxatives hoping for a shortcut, but the reality is that sustainable weight management in the UK requires lifestyle changes, dietary adjustments, or in some cases, prescription weight loss medication. Understanding why laxatives don't work — and what actually does — can help you make informed decisions about your health.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Why Laxatives Don't Work for Weight Loss
Laxatives work by stimulating bowel movements, removing water and waste from your digestive system. Any weight loss you see is temporary water loss, not fat loss. Once you rehydrate — which your body needs to do — the weight returns immediately.
More importantly, laxative misuse carries real health risks:
- Dehydration: Can cause dizziness, weakness, and electrolyte imbalances
- Dependency: Your bowel becomes reliant on laxatives, losing natural function
- Nutrient malabsorption: Chronic use prevents your body absorbing essential vitamins and minerals
- Stomach cramping and pain: Especially with prolonged use
- Serious complications: Extended misuse can lead to bowel damage
The NHS warns against using laxatives for weight management. They're intended only for constipation relief under medical guidance.
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.
What Actually Works for Weight Loss in the UK
Sustainable weight loss involves a calorie deficit — typically losing 0.5 to 1 kg per week through reduced calorie intake and increased physical activity. Try our free BMI calculator to understand your current weight status and healthy weight range for your height.
For those struggling with diet and exercise alone, prescription weight loss medication offers evidence-based support. Options like GLP-1 injections (Wegovy, Mounjaro) work by regulating appetite and helping you feel fuller on smaller portions. Use our GLP-1 weight loss calculator to explore projected results at different doses. Access in the UK is through NHS specialist services or private clinical assessment — never laxatives or unproven shortcuts.
- 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 laxatives cause weight loss?
Laxatives cause temporary water weight loss only, not fat loss. The weight returns once you rehydrate. They don't reduce actual body fat and carry serious health risks including dehydration, nutrient malabsorption, and bowel dependency. The NHS does not recommend laxatives for weight management.
How much weight can you lose with laxatives?
Any weight lost is temporary water weight, typically 0.5–2 kg, which returns within hours or days of normal hydration. This is not sustainable weight loss. True weight loss requires a calorie deficit over time, supported by diet, exercise, or prescription medication where appropriate.
What's a safe, sustainable rate of weight loss?
The NHS recommends losing 0.5 to 1 kg per week. This typically requires a 500 kcal daily deficit through reduced calorie intake and increased physical activity. For personalised advice, speak to your GP about weight management options, including prescription weight loss medication if eligible.
What are evidence-based weight loss methods in the UK?
Proven approaches include calorie-controlled diets, increased physical activity, behaviour change programmes, and NHS weight management services. For those who meet eligibility criteria (BMI 30+ or 27+ with weight-related conditions), prescription weight loss injections like Wegovy or Mounjaro are available through NHS specialist services or private assessment.
Are weight loss injections safe alternatives to laxatives?
Yes. GLP-1 medications like Wegovy are prescription-only and approved by UK regulators. Clinical trials show average weight loss of 14–21% of body weight when used alongside diet and exercise. They work by regulating appetite hormones, not through dangerous digestive manipulation like laxatives.
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.