Collagen also exhibits an affinity for water, and it appears to hydrate the skin cells and Extracellular Matrix when it penetrates the skin barrier
PMID: 17703734
The first hypothesized mechanism is via the stimulation and secretion of the VEGF, leading to the growth of blood vessels in the area surrounding the hair follicles
Pyo HK, Yoo HG, Won CH, Lee SH, Kang YJ, Eun HC, Cho KH, Kim KH
While there are several types of these receptors, like VEGFR-1, VEGFR-2, and VEGFR-3, it appears that the primary mediator of angiogenic response is most likely VEGFR-2
Among these, AHK-Cu has been posited to potentially both extend and trigger Anagen hair growth phases, with impacts in certain research studies reported up to 3-5 years