Investigating the effects of circadian rhythm on the human skin lipidome

-values and Lomb-Scargle analysis showed no circadian metabolites. Using PCA and PLS-DA, no significant clustering based on timepoints was observed across participants; however, half of individuals showed significant metabolite clustering at 07:30. Further, sebum-specific squalene and sapienic acid as well as stratum corneum-specific cholesterol sulfate showed no significant differences in concentrations across timepoints. While individuals exhibited temporal differences, as an averaged healthy cohort the impacts by the circadian rhythm or time of sampling were considered negligible.