Sweanty SweaTracker Patch Know More About Your Sweat

All fitness wearables on the market track a few similar metrics. Heart rate, number of steps, blood oxygen, sleep stages. The list hasn’t changed in five years, and most of it measures what’s going on inside your body while completely ignoring what’s leaving it. Your sweat holds data that no wristband or ring has figured out how to capture. Sweat-analyzing clips from companies like Nix and Gatorade have started the problem, but the category still hasn’t reached the level of mainstreaming that heart rate monitors did a decade ago. That gap has quietly shaped how millions of athletes get wet: by guesswork.

So the real question is not whether you are drinking enough water. Whether you’re replacing certain electrolytes your body lost during that last session, in the right amounts, at the right time. A runner in the Miami heat and a cyclist in the dry mountain air lose completely different amounts of sodium per liter of sweat. That difference determines whether you ride at mile 18 or finish strong. Smartwatches can’t tell you that because they don’t have your sensors. Every wearable industry builds its hydration advice around generic “drink plenty of water” reminders that treat the entire body the same way, which is about as useful as a thermometer that only reads “warm”.

Sweanty, a Spanish startup that has been developing sweat-analyzing pads since 2021, showed up at MWC 2026 with an update that feels overdue. The technology was developed during the PhD research of CEO Laura Ortega Tañá, and according to the company, the patented sensor has since been verified by elite athletes and industrial workers in extreme heat. The company brought down its SweaTracker Patch in Barcelona, ​​​​and the pitch turned to what it did not need: no charging cable, no Bluetooth pairing, no housing sold on the wrist.

What is it

The Sweanty SweaTracker Patch is a disposable sensor that attaches to the lower back and measures how much salt you lose through sweat during exercise. Sold in three-packs, which is the minimum amount Sweaty needs to create your first “SWEATPROFILE”, a basic reading of your body’s different electrolyte outputs. Each episode is used once. You peel it off before training and throw it away when the session is over.

The form factor looks closer to medical adhesive tape than anything you’d associate with a fitness tracker. Dynamic electronics sit inside a thin layer of medical-grade material designed to handle high levels of sweat without degrading during a run. If you’ve ever worn a continuous glucose monitor, the physical experience is familiar: it’s lightweight, it stays put while you walk, it’s so thin that clothes don’t catch on it.

The patch talks to your phone via NFC rather than Bluetooth, meaning you tap it using your device after a workout instead of keeping your phone nearby during a session. That’s a really smart choice for trail runners who ditch their phones after long runs. No mid-workout synchronization keeps the patch simple and easy.

Sweanty puts a patch on the lower back, a choice the company has not publicly explained but tracks with research that shows the composition of sweat varies in all areas of the body. A forehead patch can give you different numbers than a chest patch at the same time. You can see intentional positioning when you think about how placement affects data quality.

How the paper battery changes the game

The underlying technology is a patented paper-based battery with two electrodes embedded inside. If the paper is dry, the battery remains inactive. When sweat gets into it, the device wakes up and produces a current that is directly related to the concentration of salt in the sweat. That approach eliminates the need for a lithium-ion cell, a charging port, or any of the power management complexity that increases the cost and size of conventional wearables. There is good performance of a sensor that draws energy from the same object it is designed to analyze.

NFC handles the data transfer after the session. You hold your phone against the used patch, and the accumulated sweat data goes with one tap without touching. No pairing process, no background app exit during your operation.

Sweanty produces SWEATPROFILE from the first three patches in the Welcome Pack. Each session provides sweat rate, salt concentration, and estimated fluid loss data, including your workout plan and weight, age, height, and sport. The company recommends that you refresh your profile every three months with a two-part refill pack, as environmental changes and fitness shifts affect the composition over time. That cycle keeps hydration plans limited to your current physiology rather than the old data of a different season.

As of early 2024, the team has been developing a version where the electronics can be stored after each use, with a disposable sweat collection layer installed instead. If that effort works and Sweanty breaks the engineering challenge while keeping accuracy the same, the business model moves from deployable patches to a reusable platform with replacements. That iteration can be a tipping point between a niche pro-athlete tool and something the weekend racer thinks about.

A companion app builds your hydration playbook

The Sweanty app translates raw Sweanty data into specific hydration plans: which products to use, how much, and when during your event. For a long distance race, it sets pre-race nutrition, mid-race electrolyte timing, and recovery products, all personalized to your profile. You notice the clarity quickly when you compare it to the vague instructions to “stay hydrated” on most smartwatch apps.

Premium subscribers can create unlimited editions of their main games. Each specifies the salt and carbohydrate content per hour of the recommended products, although Sweanty does not sell or stock the products themselves. That is a welcome option because it keeps recommendations honest: the system is not encouraged to push branded supplements. If your preferred electrolyte product does not match your profile, the app suggests alternatives based on formulation rather than funding. With the startup already listed as a pre-MWC seed, the depth of the software suggests the team spent as much time on the app as on patching hardware.

Who should skip this

Swimmers and water sports athletes can stop here. SweaTracker can’t work when submerged in water, and that’s a physics limitation of a paper battery, not a design oversight.

If you train casually and never compete, the cost figures become difficult to justify. Three leaflets to build your initial profile and refill packs every three months are included, and the benefit is geared towards athletes who push themselves so hard that electrolyte depletion really affects performance.

SweaTracker is already available for purchase, with estimates for 2024 putting the Welcome Pack at around €120 for three episodes and three months of app access. Each patch is used once and a three-month data window means that recurring purchases are baked into the model. Weekend runners who live less than 45 minutes in cooler weather won’t know the difference between a good plan and just carrying a water bottle.

Whose is this

Trail runners, road cyclists, triathletes, outdoor construction workers, firefighters who work in extreme heat, and anyone who is congested during a race because of replacing the wrong electrolytes at the wrong time. If you have had a professional sweat test in the lab, you already understand the value of knowing your salt loss rate, and you know that one lab visit is more expensive than a pack of these patches while giving you data from only one controlled session.

Sweanty SweaTracker turns that clinical measurement into a portable, self-administered tool that works wherever you train. Coaches who develop individualized hydration protocols for a full list may find this especially useful. The industrial safety angle adds another layer: employers with workers in extreme heat can use data to reduce heat stress incidents instead of relying on standard break schedules.

Your smartwatch tells you how fast your heart was beating and how many calories you burned. The Sweanty SweatTracker Patch tells you what your body has really lost and how to get it back. That’s a category of wearable data that hasn’t existed at consumer prices until now, and it took a PhD, a battery of paper, and a startup booth at MWC to get you there.