nothing "causes" hair loss unless you have the genes, juice will speed it up if you have a bunch of bald male relatives.
90% of people have the gene for hairloss though. it just varies in the extent of how many hair follicles it effects and to what degree. even people who "don't lose hair" on steroids, still have significantly less hair than they did in their teenage years.
everyone has hairloss to some degree, it's part of human (and some species of ape) genetics for some reason.