Sarcopenia and Kampo Medicine: A Narrative Review

BackgroundSarcopenia is a complex condition characterized by age-related declines in muscle anabolism and reduced nutritional intake, as well as metabolic dysregulation, mitochondrial dysfunction, chronic inflammation, and physical inactivity. This narrative review examines the potential of Kampo medicine, a traditional Japanese system of standardized multi-component herbal formulations, as a nutrition-relevant multi-target intervention for sarcopenia care. Kampo medicine may be positioned as a nutrition-relevant multi-target intervention, but its clinical evidence base for sarcopenia remains heterogeneous and largely indirect. The authors searched PubMed, Scopus, and Web of Science from database inception to May 2026 using prespecified combinations of disease-, mechanism-, and formula-specific terms, supplemented by an additional search for Juzentaihoto/Juzen-taiho-to and related transliterations in response to peer review. The evidence was interpreted according to whether it directly evaluated sarcopenia outcomes or indirectly addressed nutrition-relevant domains such as appetite, fatigue, inflammation, mitochondrial function, physical activity, or neuromuscular symptoms. ResultsSarcopenia shares important pathophysiological features with frailty and cachexia, including chronic inflammation, impaired mitochondrial function, anabolic resistance, reduced food intake, fatigue, and neuromuscular dysfunction. Several Kampo formulations, including Ninjin'yoeito, Rikkunshito, Hochuekkito, Juzentaihoto, Hachimijiogan, and Goshajinkigan, have been associated with biological or clinical domains potentially relevant to appetite regulation, oral intake, inflammatory balance, gut microbiota-related pathways, metabolic resilience, and functional support. Nevertheless, direct evidence using standardized sarcopenia criteria and validated endpoints remains limited. ConclusionKampo medicine is best regarded as a hypothesis-generating, nutrition-relevant complementary approach within multimodal sarcopenia care rather than as an established stand-alone therapy for muscle loss. Future studies should use standardized diagnostic criteria, prespecified sarcopenia endpoints, rigorous safety monitoring, and transparent reporting to determine whether selected Kampo formulations can improve clinically meaningful nutrition-related and muscle-related outcomes.