Humanin is a mitochondrial-derived peptide (MDP) with a unique multimodal mechanism of action that supports cellular protection and resilience. It functions both as an extracellular signaling molecule and an intracellular protective factor, activating multiple pathways involved in cell survival. Humanin interacts with specific receptor complexes to stimulate protective signaling pathways such as JAK2/STAT3 while also binding to proteins involved in apoptosis, including BAX and IGFBP-3, helping reduce programmed cell death. In addition, Humanin promotes mitochondrial biogenesis through AMPK and PGC-1α activation, improving mitochondrial efficiency, ATP production, and resistance to oxidative stress. These mechanisms have made Humanin an important focus of preclinical research in neurodegenerative diseases, cardiovascular health, metabolic disorders, and healthy aging.