Glycemic Instability and Skin Health: Metabolic Mechanisms Linking Dietary Patterns with Cutaneous Dysfunction

Dietary patterns associated with high glycemic load and recurrent postprandial glucose excursions may influence skin physiology through mechanisms involving oxidative stress, insulin-IGF-1 signaling, chronic low-grade inflammation, and advanced glycation end product (AGE) formation. Disturbances in glucose homeostasis have been associated with alterations in epidermal barrier integrity, sebaceous gland activity, extracellular matrix remodeling, and tissue repair processes. These mechanisms have been investigated primarily in relation to several dermatological conditions, particularly acne vulgaris, impaired wound healing, xerosis, and skin aging. This narrative review summarizes current evidence regarding the relationship between glycemic dysregulation and skin health, with emphasis on metabolic and molecular pathways potentially involved in cutaneous dysfunction. To reflect the current strength of evidence, mechanistic studies, observational studies, and clinical investigations are distinguished throughout this review whenever possible. Particular focus is placed on postprandial glycemic variability, oxidative stress, hormonal signaling, and glycation-related tissue damage. Current evidence supports biologically plausible associations between metabolic dysregulation and several aspects of skin dysfunction, although direct evidence specifically addressing glycemic variability remains limited. Most available studies are observational or mechanistic in nature, and relatively few clinical investigations have evaluated dermatological outcomes directly. Further research is needed to clarify the clinical relevance of glycemic-targeted dietary and metabolic interventions in dermatology.