An all-in-one weight and health diary app

SemaPen pulls your entire weight loss journey into one powerful app. Track progress as it happens and stay in touch with the experts who keep you moving toward your goal.

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Daily motivation

We know it can be hard to stay motivated. That's why we've designed our weight loss and health diary app to be fun to use. With badges to earn and challenges to conquer, you'll keep coming back for more – especially when you see your progress.

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Expert support

SemaPen's weight loss programmes are led by UK obesity experts. And now, with our app, it's easier than ever to access their support. Gold and Platinum subscribers can also book online video appointments with dietitians and psychologists through the app.

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Cutting-edge treatments

With SemaPen, you can access the latest generation of weight loss medications, plus exclusive recipes and lessons to help you make the most of them. Access clinically proven medications with 21% average weight loss – or choose our SemaHealth programme for expert support without medication.

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Everything in one place

Forget about switching back and forth from your health tracker app to your calorie counter. With SemaPen, you can do it all. Track your mental health, medication, diet plan, nutrition*, side effects and more in the same place. Plus, we'll reach out if we feel you need more support.

Get started quickly and easily

When you download the SemaPen app, you'll start by filling in a simple questionnaire. This is so we can recommend the best programme for you.


That might be a medical weight loss programme supported by a weekly dose of Wegovy or Mounjaro. Or it could be our SemaHealth programme, which offers real results without medication.


Either way, it's quick and simple – and most users get a response instantly.


It's just as safe as in-person medical consultations, too. We gather the same information and ask the same questions as any other high-quality weight loss service.


For you, it's just like having a medical care team on call. And best of all, you can continue your journey with the app as soon as you've been approved. No waiting for letters. No time wasted.

Much more than just a weight tracker

We believe no other health diary app puts so many features at your fingertips.

Celebrate your success with a comprehensive health dashboard

Included in all plans

Love to see the weight tick down on the scale? The SemaPen app takes that sense of achievement even further with a comprehensive health dashboard.


Here's how it works. When you sign up for SemaPen, you receive a Withings® Body scale (worth £60). It sends data to the app and plots it on a graph so you can track your progress in real time.


And that's not all. You can track your mental health and any side effects you may be experiencing, too. And if you're on one of our weight loss medication programmes, you can track your dosing schedule and request changes with your SemaPen team.

Stay on track with regular check-ins

Included in all plans

When life gets busy, it can be all too easy to let your well-being fall to the wayside or forget to log data. That's why we've included automatic check-ins to help keep you on track.


Missed a dose? Mental health changes? Side effects? We'll suggest helpful next steps so you always feel supported and ready for your next challenge.

Develop good habits with SemaPen Academy

Included in all plans

Following our programmes can help you lose weight and feel healthier. But lasting change comes from the healthy habits you pick up along the way.


The SemaPen Academy gives you access to lessons on diet, exercise and mindfulness. Combined, these knowledge areas will help you understand the fundamentals of a healthy lifestyle. That means you'll be all set to live healthier for life.

Make weight loss more fun

Included in all plans

If you love a challenge, you're in for a treat. Our mission is to make weight loss feel like less of a chore. That's why we've added a whole range of fun quests to our health tracker app. For each quest you beat, you'll earn a new badge to show off on your profile.

Start your guided fitness journey from home

Included in Gold and Platinum plans

Staying active supports weight loss and overall health. That's why we've partnered with Sword Health to bring you a 10-month online fitness programme. You'll get a smart fitness band to track progress and personalised guidance from a dedicated physiotherapist. It's fun, it's effective and it's easy to participate from home.

Access expert video support quickly and easily

Included in Gold and Platinum plans

We believe no other app puts so much weight loss expertise at your fingertips. Book one-to-one sessions with dietitians and psychologists right there in the app. And track your appointments through your dashboard so you never forget to attend.


Dietitian consultations are included in our Gold and Platinum plans. Platinum plans also include a psychologist consultation.

Start strong with a comprehensive health check

Included in Gold and Platinum plans

At SemaPen, we care about your whole health – not just your weight. With our home blood test, you'll get a comprehensive overview of key health markers. That means you'll know exactly where to focus your efforts, and we can provide even more tailored support.


Our Gold plan includes a home blood test for common health problems. Our Platinum plan includes an advanced blood test for health problems and nutrients, plus an at-home health assessment with a SemaPen nurse

Coming soon

Track your nutrition with our barcode scanner

Most of us know by now how important calorie and nutrient tracking can be while on a weight loss journey. But some health diary apps make it more complicated than it needs to be.


Not us. Our nutrition tracker is simple to use, allowing you to add meals from our database as well as your own custom meals, snacks and drinks.


You'll also have a barcode scanner at your disposal. This lets you scan foods and drinks and add them directly to your tracker – very handy for cooking and meal planning.

Support each other with our weight loss forum

A weight loss journey can be lonely without friends to share it with. That's where our in-app weight loss forum can help. It's a place to connect with other people who are trying to lose weight. It's all about sharing tips, discussing challenges and motivating each other.


Want to share a win? Pop it in the forum. Facing a challenge? There's a whole community out there that's got your back.

Choose from three expert-led weight loss programmes

With weight loss, there's no one-size-fits-all. Everybody is different – and everybody needs a different kind of support to get results.


That's why we've created three expert-led weight loss programmes. It's so we can help anyone lose weight and live healthier, whatever their goals or health status.


As part of your onboarding process, we'll recommend the best science-backed options for you. That might be SemaHealth – our dietitian-led meal replacement programme – or one of our game-changing weight loss medications.

Mounjaro programme

Mounjaro is one of the most advanced GLP-1 medications available anywhere. Taken weekly for up to 72 weeks, clinical studies showed an average weight loss of 21%.¹

What you need to know
  • Effective for about 95% of users
  • Average weight loss of 21%¹
  • The newest injectable weight loss treatment
  • Discreet packaging and fast delivery
Discover Mounjaro

Wegovy programme

Approved in 2023, Wegovy is the weight loss medication that started it all. In clinical trials, users saw an average of 15% weight loss.²

What you need to know
  • Effective for about 95% of users
  • Average weight loss of 15%²
  • The best-selling GLP-1 slimming pen
  • Discreet packaging and fast delivery
Discover Wegovy

SemaHealth programme

Want to lose weight without medication? The SemaHealth programme swaps injectable medications for tasty, nutritious shakes that leave you satisfied for hours. Plus, you unlock the same expert support and great features included in our other programmes.

What's included:
  • 10-15% average weight loss³ **
  • Tasty, filling and nutrient-rich meal replacement shakes and soups
  • Direct access to weight loss experts for tailored guidance
  • Daily in-app support and meal tracking
Learn more

Which programme is right for me?

Wegovy programme Mounjaro programme SemaHealth programme
Active ingredient Semaglutide Tirzepatide No medication
How it works Once-weekly injection Once-weekly injection No medication
Dosage 5 months 6 months No medication
Average weight-loss (non-diabetic) 15% of starting weight¹ 21% of starting weight² 10 to 15% of starting weight³
Side effects Nausea, constipation, diarrhoea, vomiting, acid reflux, belching and bloating are most common. Similar to Wegovy but with less nausea. Hair thinning (temporarily) – daily multivitamins advised. Interferes with the action of the oral contraceptive pill. Can have temporary side effects, including constipation, headaches, fatigue, irritability and sensitivity to cold.
Availability in the UK Available Available Available
Prices start at*** £189 per month £225 per month £1,072.91 for a full 12-month treatment programme
Explore programmes

Get the support you need

Ever felt super motivated and committed to your weight loss plan in the beginning, only to run out of steam partway through?


We get it. It can be tough to stick to a programme – especially when you're trying to do it all by yourself. 


Through the SemaPen app, we offer personalised support plans that work alongside your weight loss programme to help you get the best results. 


It's all about giving you the right kind of support for your goals and lifestyle. That's why we offer three plans with increasing levels of support.

SemaPen support plans

Silver Gold Platinum
Expert support to help you meet your weight-loss goals Face-to-face video support and more. The ultimate weight loss plan – including expert psychological support

What's included

Silver Gold Platinum
Injectable weight loss pens or meal replacement shakes
Welcome video consultation
Dedicated patient support team
Exclusive SemaPen Academy content
Health dashboard to track progress
Calorie/nutrition tracker***
Weight monitoring and advice from clinical team
Clinical support by email
Withings® Body scale (tracks weight and BMI via the app)
Upgraded Withings® Body Smart scale (also tracks body fat percentage)
Personalised 10-month online fitness programme with dedicated physiotherapist and smart fitness device
SemaPen Essentials (monthly vitamins for weight loss)
SemaPen Advanced (tailored vitamins for GLP-1 treatment)
Simple home blood test for common health problems
Advanced home blood test with in-depth analysis of vitamin and nutrient levels
30-minute video consultation with a specialist dietitian One included – plus 50% off further consultations Included – on demand****
60-minute video consultation with a clinical psychologist One session included
Health assessment from a SemaPen nurse in your home or workplace

Make weight loss work for you with the SemaPen app

We're ready when you are. Join now to track your progress with our health diary app and stay supported by UK weight loss experts.