It´s a total myth and absolute wishful thinking, kept alive by males almost exclusively.
Come on - how could a fluid meant by nature to do something completely different (and one thing only) miraculously promote hair growth, of all things?
I´m positive, however, that it can cure cancer, infertility, corona, parkinson´s, aids (which it can transmit if it carries the virus), and religious fanaticism of all beliefs.
And while we´re at it, let´s not forget its planned future use as a superior energy-efficient fuel for a manned Mars mission.
Don´t be ridiculous, fellows. You might as well go to the cemetery on a full-moon night and ask all the virgins in the graves there (or the black cats loitering around the facility) to make your girlfriend´s hair grow faster or longer.