Nix Biosensors is an American company that makes a wearable hydration monitor for endurance sport. A reusable electronic pod connects to a disposable patch on the upper arm. It estimates fluid and electrolyte losses and sends drinking guidance to connected devices.

How it works
Microfluidic channels collect sweat as it leaves the skin. Electrochemical sensors measure sweat flow and electrolyte concentration. Software combines these local readings with personal and environmental data to estimate whole body losses. Alerts then suggest when to drink and whether water or electrolytes may suit.

Key considerations
The patch needs enough sweat, so Nix is intended for longer or warmer workouts. Local sweat can differ from whole body loss, and placement, weather and clothing affect results. Disposable patches create recurring cost.