More recently, numerous studies have identified the plausibility of sweat as an alternative to blood analysis.  The potential substitution for sweat versus blood analysis has many potential benefits.  For example, sweat can be: extracted in a non-invasive manner via iontophoresis; extracted with little-to-no pain; and monitored continuously.  There are downfalls to the technology, however.  For example, demonstration of successful and reliable sweat extraction and analysis on a cohesive device has yet to be demonstrated.  Furthermore, although some biomarker partitioning mechanisms are well understood and well studied, partitioning of other useful biomarkers (cytokines, peptides, etc.) are less understood.