Association between sleep patterns, circadian rhythms, and hair loss in young adults.

The increasing prevalence of delayed bedtimes and androgenetic alopecia (AGA) among younger individuals raises the question of whether late bedtimes could be a potential risk factor for AGA. This study aimed to investigate the relationship between sleep patterns and AGA in young individuals and explore whether circadian rhythms contribute to the underlying mechanisms. A cross-sectional survey among college students assessed AGA prevalence and chronotype. Circadian rhythms were evaluated through heart rate monitoring using wearable devices, and the expression of key clock genes in hair follicle samples. The results showed that evening chronotype was an independent risk factor for AGA. Severe AGA cases exhibited a significant delay in the acrophase of heart rate compared to non/mild cases, a trend also observed in participants with evening chronotypes. Molecular analysis revealed that severe AGA cases had lower expression of the clock gene PER3 and a delayed acrophase shift relative to non/mild AGA. These findings suggest that altered circadian rhythms - manifested by shifts in heart rate patterns and clock gene expression - may help explain the increased risk of AGA observed in individuals with an evening chronotype. While preliminary, the results highlight the possible involvement of circadian mechanisms in the pathophysiology of AGA.