The wearable biochemical sweat sensor's capability to provide insight into molecular information of health dynamics ignites sweat analysis as a promising noninvasive diagnosis scheme for precision medicine. Here, we demonstrate, for the first time, a colorimetric sweat induction microfluidic patch, which facilitates on-demand sweat glands activation by agonist coupled electrode and capillary action-based fluidics to collect microliter volumes (similar to 5 mu L) of sweat for monitoring its analytes by digital image analysis. The system's clinical utility demonstrated on a healthy volunteer for sweat pH monitoring flags the way towards other important sweat markers analysis for personalized healthcare.