A wearable device for the quantification of regulatory substances produced in the body, such as analytes and hormones, is disclosed. The wearable device includes contact sensors formed on an outer portion of a casing of the wearable device, and those contact sensors are positioned to contact skin of a wearer of the device and configured to measure galvanic skin response and temperature. The wearable device also includes a microprocessor in the casing of the wearable device adapted to control programs and execute algorithms, a system memory in the casing of the wearable device adapted to store data, an entry port in the casing of the wearable device adapted to receive a biological-assay cartridge containing a biological sample, and a biological-assay reader placed inside the casing of the device and configured to read the biological sample.