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
What Does a BMI of 17 Mean?
A BMI of 17 falls comfortably within the healthy weight range according to NHS guidelines. This BMI category indicates that for your height, your weight is at a level associated with lower health risks. BMI 17 is well below the overweight threshold of 25, placing you in the optimal health bracket. However, BMI is just one health measure—your GP can provide personalised guidance about what this means for your individual circumstances. Use our free BMI calculator to check your exact BMI and explore how it relates to your height.
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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.
Where BMI 17 Sits in NHS Guidelines
According to the NHS BMI classification system, a BMI of 17 falls within the healthy weight range of 18.5 to 24.9. This means your weight is considered appropriate for your height and is associated with lower risk of weight-related health conditions like type 2 diabetes, heart disease, and high blood pressure. A BMI of 17 is actually on the leaner side of the healthy range—closer to athletic fitness than the average healthy weight. The BMI formula (weight in kg ÷ height in metres²) shows how your weight compares to population averages. If you're curious about what weight would give you a BMI of 17 at your specific height, our weight converter and BMI calculator above can help you work this out instantly. Remember that the healthy BMI range UK applies to adults aged 18 and over—different standards apply for children.
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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.
BMI Limitations and What Else Matters
BMI limitations are important to understand: BMI does not distinguish between muscle and fat. If you're athletic or regularly strength train, you may have a BMI of 17 but actually carry more muscle than fat, which is beneficial. BMI also doesn't account for where fat is stored—abdominal fat carries higher health risks than fat stored elsewhere. The NHS recommends checking your waist circumference alongside BMI: healthy thresholds are under 94cm (37 inches) for men and under 80cm (31.5 inches) for women. Age, ethnicity, and individual health conditions also matter. Your GP is the best source for personalised interpretation of your BMI and overall health status.
- 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 a BMI of 17 considered healthy?
Yes, BMI 17 is well within the NHS healthy weight range (18.5–24.9). It's actually on the leaner side of healthy, associated with low risk of weight-related diseases. However, individual health depends on many factors beyond BMI alone.
What does BMI 17 mean for my weight and height?
BMI 17 indicates your weight is appropriate for your height according to population health standards. To find out your exact weight at BMI 17 for your specific height, use our free BMI calculator above—it works both ways (weight to BMI or BMI to weight).
Is BMI 17 too low?
A BMI of 17 is not too low. The NHS classifies underweight as below 18.5, so 17 is close to that threshold but still in the healthy range. If you're concerned about being underweight, speak to your GP about your individual nutrition needs.
How do I know if my BMI of 17 is actually healthy for me?
BMI is a screening tool but has limitations—it doesn't account for muscle mass, age, or ethnicity. Your GP can assess your overall health picture including waist circumference, fitness level, and any health conditions to give you personalised guidance.
What weight would give me a BMI of 17 at my height?
Use the formula: healthy weight = 17 × height (metres)². For example, at 1.75m, a BMI of 17 would be roughly 52kg. Our free weight converter and BMI calculator above can calculate this instantly for your exact height.
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.