The Skin Microbiome and Bioactive Compounds: Mechanisms of Modulation, Dysbiosis, and Dermatological Implications

Maintaining the balance between the host and commensal microorganisms is essential for skin health. The disruption of this equilibrium (dysbiosis) can contribute to inflammatory and infectious diseases and accelerate skin aging. Dysbiosis also accompanies skin cancers and may influence their progression. Causes of dysbiosis include exogenous factors such as cosmetics, UV radiation, pollution, and diet, as well as endogenous factors like stress, hormonal imbalances, and aging. Standard antibacterial treatments often eliminate beneficial microbes and may exacerbate conditions. Consequently, there is growing interest in alternative strategies—notably natural plant- and animal-derived products—that can modulate the skin microbiome more selectively and gently. This review presents current knowledge on skin microbiome physiology and dysbiosis and discusses natural compounds and microbiome-based therapies (probiotics, prebiotics, postbiotics) that modulate the skin microbiota. Unlike prior reviews, we provide a comparative perspective on emerging compound classes (e.g., peptides, lipids) and integrate the skin–gut axis concept into the framework, highlighting mechanistic insights at molecular and clinical levels. Our synthesis emphasizes distinct modes of action and evidence levels—from in vitro mechanisms to clinical outcomes—and offers guidance for formulation of microbiome-compatible products.