Masashi Yanagisawa (born 1960) is a sleep scientist who investigates the molecular and neural mechanisms controlling sleep and wakefulness. He studied medicine at the University of Tsukuba and completed its doctoral program in medical sciences. In 1988 he discovered endothelin, a biologically active peptide that constricts blood vessels. He moved to the United States in 1991 and led a laboratory at the University of Texas Southwestern Medical Center and the Howard Hughes Medical Institute. A search for molecules that activate receptors of unknown function led his team to discover the neuropeptide orexin in 1998. The following year, they reported that mice lacking orexin showed symptoms resembling narcolepsy. A molecule initially investigated in relation to appetite thus became a route into understanding the maintenance of wakefulness and the genetic and molecular regulation of sleep. He established a laboratory at Tsukuba in 2010 and became director of its International Institute for Integrative Sleep Medicine in 2012. In 2017 he founded the university startup S’UIMIN to work on sleep measurement and analysis. He and Emmanuel Mignot received the 2026 Albert Lasker Basic Medical Research Award for research identifying orexin and elucidating its relationship to narcolepsy. Yanagisawa also supervised the Japanese illustrated introduction “Imasara Kikenai Suimin no Chokihon,” which explains the functions and mechanisms of sleep and the effects of sleep deprivation before turning to practical questions about sleeping well. His 2026 Japanese-language book “Sekai Saiko no Suimingaku ga Oshieru: Suimin no Seikai” examined familiar beliefs about sleep against research findings. It addressed sleep duration and quality, naps, bedroom conditions, and changes with age, connecting the brain mechanisms underlying sleep with questions arising in everyday life. It distinguished established findings from questions that sleep research had yet to resolve.
