PF4 and alopecia: Among the hair growth-promoting and DP-signature genes investigated, PF4 reduced the expression of Wnt5a, Wnt10b, LEF1, HEY1 and IGF-1, and increased the expression of DKK1, but did not alter the expression of BMP2 and BMP4. Taken together, Our findings reveal that PF4 inhibits human hair follicle growth possibly by enhancing androgen receptor signaling and decreasing hair growth-promoting genes expression, providing new insights into the application and optimization of PRP in the administration of hair loss.