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
Hair Loss from Mounjaro — NHS & Private Guidance
Hair loss (alopecia) is a known side effect that may affect some people taking Mounjaro, the prescription weight loss injection licensed in the UK. This page explains why hair loss can occur during treatment, how it relates to NHS eligibility and specialist services, and what your GP or prescriber can advise. MyWeightCheck provides educational information only — always consult your GP or healthcare professional about any side effects you experience while taking Mounjaro.
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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.
Mounjaro Hair Loss and NHS Specialist Services
Hair loss during Mounjaro treatment is listed as a common side effect, affecting up to 1 in 10 people. It typically occurs due to rapid weight loss — when your body loses significant weight quickly, nutrients are redirected, and hair follicles may enter a resting phase (telogen effluvium). This is usually temporary.
If you are receiving Mounjaro through an NHS specialist weight management service (tier 3 or tier 4), your multidisciplinary team can monitor for side effects and adjust your dose titration schedule if needed. NHS services have access to dietitians and weight management specialists who can optimise your nutritional intake to support hair health during treatment.
Hair loss from rapid weight loss is typically reversible once weight stabilises, though this may take several months. Your prescriber may recommend nutritional support, including adequate protein, iron, zinc, and vitamin D intake.
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.
NHS Access vs Private Mounjaro Prescription
In the UK, Mounjaro is available through two pathways: NHS specialist tier 3 services and private prescribing via online consultations. NHS access requires GP referral to a specialist weight management service and NICE-approved eligibility criteria (BMI ≥30, or BMI 27–29.9 with weight-related health conditions). Waiting times for NHS specialist services vary significantly by region and can be months to years.
Private prescription routes offer faster access without NHS referral — a licensed prescriber conducts an online clinical assessment and issues a prescription if clinically appropriate. Both pathways dispense Mounjaro via KwikPen, a once-weekly weight loss injection. Regardless of access route, report hair loss or other side effects to your prescriber, as they may adjust your treatment plan.
- 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 hair loss a common side effect of Mounjaro?
Yes, hair loss (alopecia) is listed as a common side effect, affecting up to 1 in 10 people taking Mounjaro. It is usually caused by rapid weight loss and the way your body redirects nutrients during significant weight change. Most cases are temporary and hair typically regrows once weight stabilises.
Will my hair grow back after stopping Mounjaro?
Hair loss from rapid weight loss is typically reversible. Once your weight stabilises and you stop losing weight rapidly, hair follicles usually return to their normal growth cycle over several months. This process is gradual — full regrowth can take 3–6 months or longer.
Can the NHS help if I experience hair loss on Mounjaro?
If you are receiving Mounjaro through an NHS specialist weight management service, your care team can monitor side effects and provide nutritional support. They may recommend adequate protein, iron, zinc, and vitamin D intake to support hair health. Your prescriber can also adjust your dose schedule if needed. If accessing privately, discuss side effects directly with your prescriber.
What should I do if I notice significant hair loss on Mounjaro?
Report hair loss to your prescriber or GP immediately. Do not stop taking Mounjaro without clinical guidance. Your healthcare team may adjust your treatment, recommend nutritional supplementation, or investigate whether other factors (such as deficiencies) are contributing. They can also monitor whether the hair loss stabilises over time.
Is hair loss worse with higher Mounjaro doses?
Hair loss risk is primarily linked to the rate of weight loss, not the Mounjaro dose itself. Faster weight loss — which may occur at higher doses — increases the likelihood of telogen effluvium. Your prescriber manages dose titration (typically starting at 2.5 mg and increasing weekly over months) to minimise side effects while achieving steady weight loss.
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.