The Tressless sub-Reddit is the internet’s largest gathering place for the bald and balding. It has more than 400,000 members, many of them young men stunned that their follicles have betrayed them so early. They share photos of their thinning scalps, vent about their diminished sex lives and self-esteem, track infinitesimal fluctuations in the size of celebrities’ foreheads, and ask questions like “Is Propecia an acceptable name for a daughter?” Mainly, they talk treatment: what works and,