Sweat components as a promising monitoring tool for systemic diseases.

Sweat is a complex biological fluid primarily responsible for thermoregulation, containing diverse organic and inorganic components derived from plasma and interstitial fluids. Its secretion is tightly regulated by hypothalamic-sympathetic pathways and reflects systemic physiological status. Recent studies reveal that sweat composition dynamically changes with various systemic diseases, providing diagnostic, mechanistic, and prognostic insights. Abnormalities in sweat components, such as electrolytes, glucose, lactate, amino acids, and proteins, mirror underlying metabolic, endocrine, immune, and neural dysregulation. This review synthesizes current evidence on how these alterations arise from specific physiological mechanisms-including transdermal diffusion, transporter-mediated secretion (e.g., GLUT2, CFTR), ductal reabsorption, and autonomic control-linking sweat gland biology to systemic homeostasis. These insights support the clinical development of sweat as a non-invasive biofluid for disease monitoring.