Hair loss is caused by Dihydrotestosterone. There's an enzyme that converts testosterone into Dihydrotestosterone, and the "baldness gene" basically affects the quantity of/how efficient the enzymes are. High testosterone doesn't necessarily mean baldness, but people who are genetically predisposed to baldness will be less bald if they have less testosterone. Side note, people with high dihydrotestosterone are at a higher risk of prostate cancer. So if you're bald, make sure you check yourself before you wreck yourself. Scientist pepe out.