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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Biohacking Weight Loss: Evidence-Based Strategies for UK Adults
Biohacking weight loss refers to using evidence-based strategies, medical interventions, and lifestyle optimisation to accelerate and sustain weight loss more effectively than diet and exercise alone. In the UK, this includes prescription weight loss medication, metabolic tracking, structured nutrition, and personalised health monitoring. Whether you're exploring NHS weight loss programmes or private weight management options, understanding the science behind biohacking can help you make informed decisions about your health and develop a sustainable approach to reaching your target weight.
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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.
What Does Biohacking Weight Loss Mean?
Biohacking weight loss is the practice of using science-backed methods to optimise your body's natural processes and achieve faster, more sustainable weight loss. Unlike fad diets, biohacking combines multiple evidence-based approaches: metabolic optimisation, strategic nutrition, prescription weight loss medication when appropriate, physical activity planning, and continuous progress monitoring.
Key biohacking strategies include:
- Using our free BMI calculator and progress tracker to monitor your baseline and track real-time changes
- Understanding your personal metabolic rate and caloric deficit needs
- Implementing intermittent fasting or structured eating windows if suitable for your lifestyle
- Incorporating resistance training to preserve muscle mass during weight loss
- Using prescription weight loss medication (GLP-1 injections like Wegovy or Mounjaro) under medical supervision where clinically appropriate
- Optimising sleep, stress management, and hydration to support metabolic function
The NHS recognises that sustainable weight management often requires a combination of lifestyle changes and, in some cases, medical intervention. For UK adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, prescription weight loss medication may be available through NHS specialist services or private prescribing.
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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.
Prescription Weight Loss Medication: The Medical Biohacking Approach
For many UK adults, biohacking weight loss includes prescription-only GLP-1 medications, which represent a significant advance in weight management. Wegovy (semaglutide 2.4 mg) and Mounjaro (tirzepatide) are licensed for weight management in the UK and work by regulating appetite and glucose metabolism.
In the STEP clinical trial, Wegovy helped participants lose an average of approximately 15% of their body weight over 68 weeks, alongside diet and exercise. Individual results vary significantly. Both medications require a prescription and clinical assessment from a GP or licensed prescriber to confirm suitability.
Try our free GLP-1 weight loss calculator above to estimate potential weight loss outcomes at different doses. Access is available through NHS specialist weight management services (tier 3) or private prescribing. Your prescriber will assess whether this approach is appropriate for your individual health profile.
- 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 biohacking weight loss the same as crash dieting?
No. Biohacking uses evidence-based, sustainable methods to optimise weight loss over time, whereas crash dieting relies on severe restriction and often leads to rapid regain. Biohacking includes medical support, metabolic tracking, and lifestyle balance to achieve lasting results.
Can I biohack weight loss without prescription medication?
Yes. Biohacking includes many non-medical approaches: structured nutrition, exercise programming, sleep optimisation, stress management, and continuous progress tracking. However, for some individuals, prescription weight loss medication can be a valuable tool when combined with lifestyle changes.
Is Wegovy available on the NHS for weight loss in the UK?
Wegovy may be available through NHS specialist tier 3 weight management services for eligible adults (BMI ≥30 or ≥27 with weight-related conditions). Availability varies by region. Private prescribing is also available. A clinical assessment is required in either case.
How do I know if biohacking weight loss is right for me?
Calculate your BMI using our free BMI calculator on this page to understand your health category. If you're overweight or obese, discuss weight management options with your GP. They can assess whether prescription medication, NHS weight management services, or intensive lifestyle support is most appropriate for you.
What's the difference between Wegovy and Mounjaro for biohacking weight loss?
Both are prescription GLP-1-based medications licensed for UK weight management. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist alone. Clinical trials showed average weight loss of 15–21% with Mounjaro and approximately 15% with Wegovy. Your prescriber will recommend the most suitable option based on your health profile.
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.