Among young men navigating questions of energy, mood, and purpose, a medical treatment has taken on the weight of a cultural myth. Testosterone replacement therapy — legitimate in its proper clinical context — is spreading well beyond the population it was designed to serve, driven by a marketplace of certainty that has outrun the science. Medical experts are raising a quiet but serious alarm: most men seeking this treatment do not need it, and the risks of receiving it unnecessarily are neither small nor theoretical.