Wearable devices off er diverse continuous monitoring capabilities through advanced sensing methods and wearable devices.

Recent advancements in fl exible electronics, materials science, and chemistry or electrochemistry have led to the development

of wearable sensors for non-invasively monitoring biofl uidic markers, including sweat, interstitial fl uid (ISF), and tears. These

devices utilized integration of various devices such as microfl uidic patches, microneedle (MN) arrays, and conformal eyecontact

confi gurations, enabling continuous monitoring of analytes indicative of health status. The progression of wearable

devices has evolved towards the use of biocompatible, soft materials that can be worn comfortably on the body for extended

periods. This review provides a comprehensive overview of the fundamental essential processes and recent advancements

in biomonitoring technologies under the emerging wearable devices and sensing methods that have facilitated the commercialization

of wearable devices for healthcare. It covers the physiology of sweat, ISF, and tears, as well as the materials

and biosensing mechanisms involved. Advances in sweat induction and sampling methods are also discussed, alongside the

design considerations for system-level development of wearable sensing devices.