If you're considering AHK-Cu for hair growth, understand that you're running an experimental protocol based on mechanistic reasoning, not replicated human trial data
American Journal of Psychiatry, 173(1), 3443
Yu Q, Wang X, Wang L, Zheng J, Wang J, Wang B (2016) Knockdown of asparagine synthetase (ASNS) suppresses cell proliferation and inhibits tumor growth in gastric cancer cells
The exact timing depends on the injury type, baseline tissue condition, and individual response rate
However gut cells are decidedly more snippety: they cut the precursor to produce a series of small peptides: GLP-1, GLP-2 and others (IP-2, glicentin, and oxyntomodulin)
Juanola-Falgarona 2014