A potential breakthrough for jet lag and shift work-related sleep disorders

A Japanese research team has discovered a new compound that can advance the body’s internal clock—offering hope for faster recovery from jet lag and better adaptation to night-shift work. The compound, called Mic-628, specifically activates the transcription of a clock gene named Period1 (Per1). When given orally to mice, it advanced their body clocks and activity rhythms, regardless of dosing time. The findings suggest a new approach to controlling circadian rhythms through drug action rather than light exposure.

Key findings
A collaborative team including Emeritus Professor Tei Hajime. (Kanazawa University), Associate Professor Takahata Yoshifumi. (The University of Osaka), Professor Numano Rika. (Toyohashi University of Technology), and Associate Professor Uriu Koichiro. (Institute of Science Tokyo) discovered that Mic-628 selectively induces the mammalian clock gene Per1.
Mic-628 works by binding to the repressor protein CRY1, promoting the formation of a CLOCK–BMAL1–CRY1–Mic-628 complex that activates Per1 transcription through a “dual E-box” DNA element. As a result, both the central clock in the brain’s suprachiasmatic nucleus (SCN) and peripheral clocks in tissues such as the lungs were advanced—in tandem and independent of dosing time.
In a simulated jet lag mouse model (6-hour light-dark phase advance), a single oral dose of Mic-628 shortened re-entrainment time from seven days to four. Mathematical modeling revealed that the compound’s stable and unidirectional phase-advancing effect is mediated by a negative auto-regulatory feedback of the PER1 protein itself.

Background and significance
Adapting to eastward travel, such as west-to-east transmeridian flights, or to night-shift work requires advancing the internal clock, a process that normally takes longer and is physiologically harder than delaying it. Existing methods, such as light therapy or melatonin, are heavily constrained by timing and often yield inconsistent results. Mic-628’s consistent phase-advance effect, regardless of when it is administered, represents a new pharmacological strategy for resetting the circadian clock.

What’s next?
The researchers plan to investigate the safety and efficacy of Mic-628 in further animal and human studies. Because it reproducibly advances the body clock through a well-defined molecular mechanism, Mic-628 may serve as a prototype “smart drug” for managing jet lag, shift work-related sleep problems, and other circadian misalignment disorders.
These results was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) in 2026.

About The University of Osaka
The University of Osaka was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, The University of Osaka is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
Website: https://resou.osaka-u.ac.jp/en