Sweat Patch Refills are the single-use adhesive patches required for each Nix Hydration Biosensor session. Attach to your bicep before workouts, clip the rechargeable pod onto the patch, and the patch collects sweat for analysis.

Each patch is good for one workout session only and must be replaced. Sold in packs of 4 for $25, making each patch cost about $6.25—significantly cheaper than a professional lab sweat test.

Best used strategically for key training sessions or periodically to check your hydration strategy rather than every single workout. The data you get from each session builds your personal sweat profile over time.