Astaxanthin (AST) is a potent carotenoid renowned for its exceptional antioxidant properties, which has attracted considerable scientific interest due to its broad spectrum of health benefits. This review comprehensively evaluates the therapeutic potential of AST in counteracting age-related decline, oxidative stress, and immune dysfunction, while also examining its beneficial effects on gut and skin health. Current evidence demonstrates that AST effectively mitigates oxidative stress and supports cellular health and longevity by neutralizing free radicals and upregulating endogenous antioxidant systems. In addition, AST modulates immune responses under conditions of immune dysfunction, thereby enhancing resilience against inflammatory disorders and infections. Emerging studies further indicate that AST promotes gut health by improving intestinal barrier integrity and maintaining a balanced gut microbiota, both of which are essential for systemic well-being. Moreover, its capacity to enhance skin elasticity and protect against ultraviolet-induced damage underscores its promising applications in cosmetic and dermatological products. This review highlights the urgent need for additional well-designed clinical trials to fully elucidate the underlying mechanisms, optimal bioavailability, dosage regimens, and long-term safety of AST. By integrating findings across multiple research domains, the present work provides a concise yet comprehensive overview of AST as a promising nutraceutical for promoting health, healthy aging, and the management of chronic diseases.

Inflammatory and autoimmune diseases are now understood to be significantly influenced by the intricate interactions between the microbiome and host physiology. This review investigates the function of epigenetic dysregulation in microbiome–host interaction and its consequences for health and disease. Epigenetic modifications, including DNA methylation, histone modifications, and non-coding RNA-associated regulation, are key mechanisms that control gene expression without altering the underlying DNA sequence. Microbial metabolites and community composition alterations can cause disruptions in these epigenetic processes, resulting in dysregulated immune responses and the initiation of chronic inflammatory conditions. In particular, the diversity of gut microbiota alters host epigenetic patterns, affecting T cell differentiation, inflammatory modulation, and tissue homeostasis. Aberrant epigenetic modifications contribute to the pathogenesis of autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) by promoting inflammation and autoimmunity. Similarly, gut microbiota dysbiosis has been implicated in the development and progression of inflammatory bowel disease (IBD). Identifying the reciprocal interaction between epigenetic alterations and microbiome dynamics provides unique insights into therapeutic options targeted at restoring microbial homeostasis to prevent disease progress. Consequently, understanding the intricacies of epigenetic dysregulation in microbiome–host interactions represents a significant sector in biomedical research and highlights the promise for precision medicine approaches in treating inflammatory and autoimmune diseases. The potential for microbiome-based therapies to affect host epigenetic landscapes requires additional research, paving the way for innovative therapeutic paradigms targeted at improving host resilience and restoring immunological balance. The purpose of this review is to synthesize current knowledge on how epigenetic dysregulation and microbiome–host interactions drive inflammatory and autoimmune diseases and to highlight emerging therapeutic opportunities.