Best sweat sensor and best app ever, so easy to use so easy to read the data as a professional athlete I can’t train without my sensor !
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What an incredible piece of kit! I’ve struggled with cramp for years. Transitioning from bodybuilding to more functional fitness and running, cramp has ruined so many of my events. I could never f... See more
Great Device. This is my 4th workout gathering data in my new FlowBio. And the results seems very accurate. With CF the rate at which an Athlete losses sodium and water is 3x or 4X than normal. S... See more
Have been using the sensor for 5 rides and its not fit for purpose. If the sensor moves, and it will as you are either running or riding, you lose all the data. When you do get any data takes for ev... See more
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Company details
Written by the company
FLOWBIO uses the world’s most accurate sweat sensor to measure your fluid and sodium loss in real time, with that data powered by AHi® - Advanced Hydration Intelligence - the technology that combines your sweat profile, effort, and environment to deliver personalised hydration insights, so you know exactly what to drink, when, and why. Most athletes don’t know how much fluid or sodium they lose when they sweat - and that guesswork leads to cramping, disrupted post-race sleep, empty legs, and dehydration hangovers across training, racing, and recovery. Hydration is deeply personal. Yet most hydration plans aren’t. The Hydration Planner creates session-specific strategies that adapt to your workout intensity, duration, and the conditions. You’ll get accurate fluid and sodium recommendations before each session or race. After each session, log what you consumed and select your favourite electrolyte brands including Precision Fuel & Hydration, SiS, Maurten, and others to keep your data accurate and your strategy personalised. The sensor can be worn on your upper arm with the included FLOWBIO strap, or paired with your HR chest strap. With a 100-hour battery life, USB-C charging, and integration with Garmin, Zwift, Wahoo, and Coros, it fits into the way you already train & race. Unlike other sensors, the FLOWBIO system is a one-time purchase, no subscriptions.
Contact info
Block, Unit 402-405, Biscuit Factory, 100 Drummond Road, Kala, SE16 4DG, London, United Kingdom
- 07979038460
- team@flowbio.com
- flowbio.com
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Best sweat sensor and best app ever!!!
Best sweat sensor and best app ever, so easy to use so easy to read the data as a professional athlete I can’t train without my sensor !
Not fit for purpose
Have been using the sensor for 5 rides and its not fit for purpose. If the sensor moves, and it will as you are either running or riding, you lose all the data. When you do get any data takes for ever to sync with Garmin

Reply from FLOWBIO
In principle an interesting product
In principle an interesting product, giving a good insight to my sweat rate. But I would like to have more information about the calculation method and the basics behind

Reply from FLOWBIO
Cystic Fibrosis
Great Device. This is my 4th workout gathering data in my new FlowBio. And the results seems very accurate. With CF the rate at which an Athlete losses sodium and water is 3x or 4X than normal. So getting the right numbers is a must!! Still have to try it in hot weather (above 27C) but so far the recommendation are accurate. Thanks FlowBio
Hattie was extremely knowledgeable.
Hattie was extremely knowledgeable.
I am looking forward on continuing to communicate with her.
What an incredible piece of kit
What an incredible piece of kit! I’ve struggled with cramp for years. Transitioning from bodybuilding to more functional fitness and running, cramp has ruined so many of my events. I could never figure out whether I needed more water, sodium, or potassium — or if it was simply because I was too heavy (100kg).
After using the FLOWBIO device for just three runs, it gave me my half marathon prediction for sodium and water. I ran it today with zero cramp and hit a PB of 1:39:30!
I’m genuinely excited to keep using it to stay on top of my recovery and fine-tune my race-day protocols. 100% recommend!
Great information and engagement
When I placed my order, I contacted the company to learn more about what was possible and how I could benefit from the data. They took the time to explain everything and provide me with the necessary information. They truly helped me make an informed decision and demonstrated that they take their client relationships seriously.

Reply from FLOWBIO
NZ just down the road...
Very good customer service for an international company, included free drink bottle a nice touch

Reply from FLOWBIO
Great data source
Simple to use and very responsive people behind the scenes. I bought my sensor before the android app had been released so had to talk to support who were great. Very useful data generated.

Reply from FLOWBIO
Best investment for a while!
I tried this sensor, and it was a game-changer for data and performance insight.
After a few weeks of clear insight into fuelling strategies, I was able to rehydrate properly and wake up feeling ready for the next day of training - previously I was waking up feeling unrecovered and ready to cramp.

Reply from FLOWBIO
Game changer for my training!
I started using the Flowbio device around two months ago to gain some extra data for my training.
I hadn’t realised the magnitude of the amount I was sweating or the amount of sodium lost during my sessions. Previously I was replenishing with 250-500mg sodium post workout, along with 500ml of water however since using Flowbio, I realised that I lose roughly 1500-1800mg sodium & 1L per hour of workouts!
This varies from session to session for me, depending on intensity, environment etc so it is good to have a tangible amount for me to replenish after each workout and it has allowed me to recover much faster and my output has increased significantly over the last 8 weeks and I believe it is down to being adequately hydrated as I haven’t had such high volume and consistent training ever as I have recently.
Great product and would definitely recommend if you are on the fence!

Reply from FLOWBIO
If you ain’t measuring your guessing
If you ain’t measuring your guessing. FLOWBIO brings age old techniques into a simple easy to use sensor and app.

Reply from FLOWBIO
I’ve been using the FLOWBIO Sensor for…
I’ve been using the FLOWBIO Sensor for a month or so now. The data I’ve been able to discover has been incredible. I’ve been able to record, implement and plan around forecasted weather conditions and this has been crucial whilst racing in hot conditions.
The sensor itself has an amazing battery life and is extremely discreet. The app user interface is easy to navigate and simple. I’ve loved this as it makes the analysing easier.
I wanted to also highlight the fantastic customer service. The team at FLOWBIO have been incredible. I had a call and they were beyond helpful. Very understanding team and this makes it that much more a fantastic experience. I can’t wait to discover more with the device and continue to grow my understanding.
Thank you

Reply from FLOWBIO
New user of Flowbio have the device for…
New user of Flowbio have the device for about a month now and my experience has been excellent.
1. Had some trouble with Anpost in Ireland being a pain with customs (nothing to do with Flowbio) all documentation was perfect but they decided to send the device back after accepting payment ! I can honestly say Hattie and the team went above and beyond sorting things out for me. No problems getting the device and unbelievable helpful.
2. When a device is expensive you want to know you’ll be taken care of so I always reach out and ask questions especially technical questions. Not only did I get my questions answered they were answered in detail and all the reference material shared. Also like to say the speed of responses and genuine wanting to help is very welcome.
3. I’ve now been using the device for a month for running and cycling (cycling mostly indoors). The insights I get are fantastic especially with the marathon I ran 2 weeks ago. I followed the guidance as best as I could and while I was still sore the following day I actually thought my recovery was much quicker. I’m awful at drinking water etc ..
4. Battery life is perfect, loads of power for a few long runs and basically get nearly two weeks of training.
Final thoughts , excellent service , excellent product and I’m very much looking forward to seeing the new features over the coming weeks / months. I did my research as I always do and I have to say I’m very happy with my decision. I use a garmin watch so having the details on my wrist will be next level once that feature is released, but for now the app is perfect.
Thanks to the Flowbio team, very happy customer.
Alan.

Reply from FLOWBIO
Great tech and customer service
I was interested in tracking my fluid and sodium losses during ultramarathon training and racing, and I came across the S1 sensor from FLOWBIO. The team was fantastic answering all of my questions and letting me try the device in their office. It’s a fantastic piece of kit that takes the guesswork out of hydration!

Reply from FLOWBIO
Great data helped with a strong race finish!
I was excited but nervous to purchase this sensor, asking myself how good could the data actually be? - but it has paid itself back 10x in the data and insights that it has provided. I spent 2 months collecting data from my training ahead of my first 2025 event. What surprised me the most was my sodium loss during endurance training. Using the app's Event Planner tool was super easy and provided recommendations for my 2 day stage race in the Arizona desert (read sunny and hot!). FlowBios analytics provided recommendations for the event which I followed to the letter - and the results were impressive! Not only was the predictive planner recommendations almost spot on to actual sweat data from the event, by using the sodium intake recommendations I was able to finish very strong without bonking, holding threshold pace after an 8 hour endurance day and then crossed the finish line feeling strong (enough to call the kids and the questioned how I was still looking so chipper after an 8 hour race). The biggest surprise and improvement has been how much sodium I lose during extended endurance training and racing - and by following the recommended intakes, I have felt and performed much stronger during race events without the dreaded bonking or death marching the finish. The S1 sensor is super convenient and easy to use - just like any wearable heart rate monitor. Would highly recommend adding to any endurance athletes protocol - you'll likely be surprised how salty you are!
Also - the aftermarket customer support has been fantastic with the FlowBio team responding to questions and having great constructive discussions for future features and feedback from actual users of the technology

Reply from FLOWBIO
Wonderful product and experience
I booked a slot with the Flowbio team at the National Running Show and to be honest, I didn't have much of an expectation of what to expect.
Upon arrival, I met with Hattie, Will, Ines and Jamie, who are all lovely. They set up the sensor and I started exercising on the treadmill for around 30/40. The sensor was attached to my arm and I barely felt it, it sat nicely.
The test results were incredible and I learnt that day that I have been neglecting my hydration and which is having a huge impact on performance and recovery. I now have a hydration plan for each run I do, and it's so simple now I know what I am doing.
I am using the device to help me to keep on top of my hydration while training and during ultra marathons. This is crucial for my recovery which sometimes is a short turn around between races.
If you are an amateur athlete, professional athlete or enthusiast that either loves fitness tech and/or wants to improve performance (and this includes includes stopping dehydration headaches and pains) and also improve recovery, then this is for you.

Reply from FLOWBIO
GAME CHANGING DATA
Was lucky enough to meet Stefan, for a podcast episode, after talking and finding out more about the brand and the S1, o had to get my hands on it!
Moving forward, and having a chat with Stefan at Rouleur, I collected my s1, great bit of kit, easy to use and you forgot it’s even on the chest strap most the time.
I made a YouTube video ( kingaidancyclist youtube ) on the thoughts and I was hugely surprised to find my hydration was off during training and found that my body required more/leas sodium depending on the intensity of the session and if indoors or outdoors. The difference was surprising. A real in-sight into what I have to do to perform better on and off the bike.

Reply from FLOWBIO
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