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
NMN Weight Loss: Does It Work?
NMN (nicotinamide mononucleotide) is a supplement that claims to support weight loss by boosting NAD+ levels in cells, but the evidence for weight loss in humans is limited. While some animal studies suggest NMN may influence metabolism, clinical trials in humans are sparse. If you're looking for evidence-based weight management in the UK, prescription weight loss medication or lifestyle changes supported by the NHS remain your most reliable options. Our free weight loss calculator can help you explore what evidence-based approaches might suit your situation.
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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 Does NMN Actually Do?
NMN is a precursor to NAD+, a molecule involved in cellular energy production and metabolism. In laboratory and animal studies, NMN has been shown to support mitochondrial function and potentially influence fat metabolism. However, translating these findings to human weight loss is complex.
- Animal studies suggest NMN may increase fat oxidation and improve metabolic rate
- Human clinical trials on NMN and weight loss are extremely limited and inconclusive
- No large-scale UK or NHS-backed evidence supports NMN as a weight loss treatment
- Most weight loss claims around NMN rely on theoretical mechanisms rather than proven outcomes
If you're interested in prescription weight management, the NHS supports GLP-1 medications like semaglutide (Wegovy), which have robust clinical trial data showing average weight loss of approximately 15% body weight in UK trials. Try our GLP-1 weight loss calculator to see how evidence-based medication might compare to supplement-only approaches.
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.
NMN vs. Prescription Weight Loss Medication
Prescription weight loss injections in the UK have substantial clinical evidence behind them, unlike NMN. Wegovy (semaglutide) and Mounjaro (tirzepatide) are licensed by the MHRA and recommended by the NHS for eligible adults. These medications have undergone rigorous trials showing consistent, measurable weight loss results.
If you're looking for before-and-after style evidence, prescription GLP-1 medication offers that through clinical data. NMN supplements lack this level of proof. Check your BMI with our free BMI calculator to see if you might be eligible for NHS or private weight loss treatment, which provides far stronger evidence of effectiveness than supplement-based approaches.
- 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.
Does NMN actually help with weight loss?
Current evidence for NMN and human weight loss is very limited. While animal studies show promise for NAD+ boosting, human clinical trials are sparse and inconclusive. The NHS does not recommend NMN as a weight loss treatment. If you need evidence-based weight management, speak to your GP about prescription options.
Is NMN the same as Ozempic or Wegovy?
No. NMN is a dietary supplement, while Ozempic and Wegovy are prescription medications. Wegovy (semaglutide) is licensed for weight management in the UK with clinical trial evidence. NMN has no such regulatory approval or proven weight loss efficacy in humans.
Can I use NMN alongside prescription weight loss medication?
Always consult your GP or prescriber before combining any supplements with prescription medication. They can advise on interactions and whether NMN is appropriate for your individual situation. Most weight loss success comes from the prescription medication itself, not supplements.
What's the best evidence-based weight loss approach in the UK?
The NHS recommends a combination of calorie-controlled diet, regular physical activity, and—for eligible adults—prescription weight loss medication. GLP-1 medications like Wegovy have strong clinical evidence. Your GP can assess if you qualify and discuss the best approach for your BMI and health.
Why do "before and after" claims exist for NMN if it doesn't work?
Many supplement companies make weight loss claims based on theoretical mechanisms or isolated studies, not robust human trials. Always look for clinical evidence and MHRA approval. Prescription weight loss medications in the UK are backed by rigorous trials and regulatory oversight—a much stronger evidence standard.
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.