The Nix Hydration Biosensor is a stick-on wearable device that analyzes your sweat in real-time during exercise to provide personalized hydration recommendations. Attach the biosensor pod to a single-use sweat patch on your bicep, start your workout, and receive data on fluid loss, electrolyte loss, and sweat composition via the Nix app.

Recommended for workouts 45+ minutes. The biosensor measures CO2 concentration in sweat to determine when and how much to drink—validated by peer-reviewed studies from San Francisco State University.

Provides a Nix Index score and personalized notifications on your phone or watch. Integrates with Apple Health, Garmin, and TrainingPeaks.

The pod is rechargeable (36-hour battery), but patches are single-use at $25 for 4 patches. Best for endurance athletes serious about hydration strategy.