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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Weight Loss and Citalopram: Understanding Your Options in the UK
Citalopram is an SSRI antidepressant that can affect weight as a side effect, but it's not a weight loss medication. If you're taking citalopram and concerned about weight changes, or if you're looking to lose weight while on citalopram, there are evidence-based prescription options available in the UK. This guide explains how citalopram affects weight, and introduces the licensed weight management medications that may be suitable for you alongside your current treatment. Always consult your GP before making any changes to your medications or starting new treatments.
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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.
UK-Licensed Prescription Weight Management Options
If you're looking to manage your weight loss in the UK and are already taking citalopram, your GP can discuss whether prescription weight loss medication is appropriate for you. Three medicines are currently licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide).
Mounjaro is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist. Clinical trials showed it helped participants lose an average of 15–21% of their body weight when combined with a reduced-calorie diet and increased physical activity. Wegovy is a once-weekly GLP-1 injection with clinical trial results showing average weight loss of around 15% of body weight. Both are prescription-only and require a clinical assessment before being prescribed.
Eligibility typically includes adults with a BMI of 30 or above, or BMI of 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Your GP or a licensed prescriber will assess whether these medications are safe for you, particularly given your current citalopram use, as medication interactions must be considered.
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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.
Getting Support: NHS vs Private Access
In the UK, you can access prescription weight loss medication through two routes. The NHS offers these medications through specialist tier 3 weight management services, typically accessed via GP referral. However, NHS availability varies significantly by region, and waiting lists can be lengthy in many areas.
Alternatively, private prescribing through GPhC-registered online services is available without an NHS referral. A licensed UK prescriber conducts an online assessment and issues a prescription if clinically appropriate. Your GP can advise on the best route for you.
Before starting any weight management UK programme, discuss your citalopram use with your healthcare provider. Weight loss works best alongside lifestyle changes: use our free BMI calculator above to understand your current health metrics, and try our GLP-1 weight loss calculator to explore potential outcomes if medication is recommended for you.
- 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 I take weight loss medication while on citalopram?
This depends on your individual circumstances. Citalopram and most weight loss medications can be taken together, but your GP or prescriber must assess for any interactions. Always inform your healthcare provider of all medications you're taking before starting weight loss treatment. They will advise whether it's safe for you.
Does citalopram cause weight gain?
Citalopram can affect weight in some people—it may increase appetite or cause slight weight gain, though not everyone experiences this. If you're concerned about weight changes on citalopram, speak to your GP. They may adjust your dose, switch medications, or recommend weight management support alongside your mental health treatment.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are once-weekly injections for weight management in the UK. Mounjaro is a dual GIP and GLP-1 agonist with average clinical trial weight loss of 15–21%. Wegovy is a GLP-1-only agonist with average weight loss around 15%. Both require a prescription and clinical assessment. Your GP or prescriber can advise which is more suitable for you.
How do I access weight loss medication on the NHS?
Ask your GP for a referral to your local NHS specialist weight management service (tier 3). Eligibility is typically BMI 30+, or BMI 27+ with weight-related health conditions. Availability and waiting times vary by region. Your GP can tell you what support is available in your area.
Can I use your BMI calculator to check if I'm eligible for weight loss medication?
Yes. Our free BMI calculator above will show your current BMI and how it compares to NHS healthy weight ranges. If your BMI is 30 or above, or 27 or above with weight-related health conditions, you may be eligible. Use it as a starting point, then discuss options with your GP.
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.