Theory 26/Hair follicle cycle/Progression phase
Growth Rate Is Matrix Division
The claim
Fibre elongation rate is set by the ratio of matrix cell division to keratinisation rate, so growth slows when differentiation outpaces division.
01Mechanism
Length is added by dividing cells below the zone of keratinisation; the ratio sets elongation.
02Prediction
Growth rate should track the ratio.
03Refutation
Growth tracking nutrition alone would remove division.