Follicular Coherence Index: A Computational Twin for Hair Aging as Loss of Regenerative Propagation

This paper introduces the Follicular Coherence Index (FCI), a systems-level metric for quantifying regenerative propagation coherence in hair follicle networks. Using a computational twin consisting of coupled excitable follicular units, the study explores whether visible hair aging — including graying, thinning, and regenerative decline — can emerge from loss of inter-follicular propagation coherence.Across three iterative falsification cycles, the model demonstrates that reduced coupling reproduces declines in propagation competence and regenerative synchrony, while combined restoration of coupling and intrinsic decay parameters is required for full rescue of pigment and stem-cell reserve. Phase diagrams reveal recoverable and non-recoverable regions, producing a modeled “point-of-no-return” boundary for coupling-based rescue.The work does not claim proof of biological causality, but provides a falsifiable computational framework for experimentally testing the role of propagation coherence in hair aging.