Soy Milk and Hair Loss. Hair loss has been haunting people since centuries and many individuals have tried infinite ways to grow their hair back. One such method that was found to actually slow down the process of hair loss was linked to the consumption of soy milk.his compound blocks a form of testosterone called dihydrotestosterone (DHT), which is related to baldness and prostrate cancer. Soy milk works just like a hair loss drug called Propecia that blocks the transition of testosterone into DHT.