Korean traditional medicine maintains a centuries-old chronotherapeutic framework — 자오류주(子午流注, Cha-Oh-Ryu-Ju) twelve-meridian timing — in which the twelve principal meridians (간/담/심/소장/비/위/폐/대장/신/방광/심포/삼초) are assigned 2-hour windows of peak qi flow (시진, sì-jin) across the 24-hour cycle. Modern circadian biology has revealed substantial molecular evidence for cell-autonomous and tissue-level circadian rhythms, including in skin (hair-follicle stem-cell rhythmicity, keratinocyte proliferation timing, sebaceous lipid output) and in drug-metabolizing enzymes (CYP P450 family, UGT, sulfotransferase). We propose a quantitative framework that integrates these two independent traditions: a mapping table between 자오류주 시진 windows and the principal molecular circadian outputs relevant to skin and to topical-drug pharmacokinetics, and a time-of-day-conditioned topical-treatment schedule for Korean-medicine-clinic protocols. We do not claim that 자오류주 has direct molecular validity; we present the framework as a structured hypothesis that can be tested experimentally and that may improve topical-treatment timing within Korean medicine practice. All proposals are conceptual; no clinical or laboratory experiments are reported. Keywords: 자오류주, chronotherapy, circadian biology, skin pharmacokinetics, topical drug timing, Korean medicine, 12-meridian, framework.
Cheongwoo Han (Tue,) studied this question.