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
Does Weight Loss Cause Hair Loss?
Yes, weight loss can cause temporary hair loss in some people — but it's usually not permanent. When you lose weight rapidly, your body experiences physical stress that can push hair follicles into a resting phase called telogen effluvium. This is a common and generally reversible condition. Most people see their hair regrow within 3 to 6 months once weight stabilises. Understanding why this happens and how to support your hair health during weight management can help you minimise this effect.
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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.
Why Weight Loss Causes Hair Loss
Hair loss during weight loss happens due to a process called telogen effluvium. When you lose weight quickly — whether through diet, exercise, or weight loss medication like GLP-1 injections — your body experiences metabolic stress. This stress can trigger hair follicles to shift prematurely from the growth phase (anagen) into the resting phase (telogen), causing increased shedding 2 to 3 months later.
The severity depends on several factors: how quickly you lose weight, whether you're losing muscle as well as fat, nutritional deficiencies, and your individual hair cycle. gradual weight management (more than 1.5 kg per week) carries higher risk than gradual loss. During NHS weight loss or prescription weight loss programmes, slower, sustainable weight loss typically minimises hair loss risk. Adequate protein intake, iron, zinc, and B vitamins are essential — deficiencies amplify shedding. Using our free BMI calculator can help you establish a healthy target weight and realistic timeline.
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.
Supporting Hair Health During Weight Management
To minimise hair loss while managing your weight in the UK, prioritise slow, steady weight loss — the NHS recommends 0.5 to 1 kg per week. Ensure your diet includes adequate protein (1.6 g per kg body weight), iron-rich foods, zinc, and B-complex vitamins. If you're using weight loss injections like Wegovy (semaglutide), the GLP-1 mechanism may cause appetite reduction; work with a prescriber or dietitian to ensure nutritional intake remains sufficient.
Consider iron and vitamin D testing through your GP if hair loss is significant — deficiencies worsen shedding. Most people regrow lost hair within 3 to 6 months after weight stabilises. Track your weight loss progress using our free progress tracker to monitor your pace — faster is not always better. If hair loss persists beyond 6 months or is severe, discuss it with your GP to rule out other causes.
- 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 weight loss medications like Wegovy cause hair loss?
Yes, GLP-1 weight loss medications like Wegovy (semaglutide) can contribute to hair loss through the same telogen effluvium mechanism as diet-based weight loss. The shedding is usually temporary and related to gradual weight management and potential nutritional stress, not the medication itself. Hair typically regrows once weight stabilises. Maintaining adequate nutrition is important.
How long does hair loss last during weight loss?
Hair shedding typically peaks 2 to 3 months into weight loss and can last 3 to 6 months. Most people see regrowth begin within 3 to 6 months after weight stabilises. If hair loss continues beyond 6 months, consult your GP to check for other causes like thyroid issues or nutritional deficiencies.
What should I eat to prevent hair loss while losing weight?
Eat adequate protein (aim for 1.6 g per kg of your body weight), iron-rich foods (red meat, lentils, spinach), zinc (nuts, seeds, poultry), and B vitamins (eggs, whole grains, leafy greens). Avoid very low-calorie diets — aim for gradual weight loss of 0.5 to 1 kg per week as the NHS recommends, which reduces nutritional stress.
Is hair loss from weight loss permanent?
No, telogen effluvium hair loss is almost always temporary and reversible. Hair regrows within 3 to 6 months once your weight stabilises and your body recovers from the stress of gradual weight management. The hair loss is not from damage to follicles — they simply pause temporarily.
Should I stop losing weight if I experience hair loss?
You don't need to stop weight loss entirely, but slow it down. Aim for 0.5 to 1 kg per week rather than faster loss. Ensure you're eating enough protein and micronutrients. If you're using prescription weight loss medication through the NHS or private prescribing, discuss hair loss with your GP or prescriber — they can help optimise your approach.
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.