Across America, a quiet ritual plays out daily in medicine cabinets and kitchen counters — the taking of pills and capsules purchased in faith that they will fill some gap between the life we live and the health we desire. Eight in ten Americans participate in this ritual, spending billions on dietary supplements whose benefits, for most people, remain scientifically unproven. It is a story as old as human hope itself: the belief that somewhere, in a bottle, lies the reinforcement our bodies need — a belief that the evidence, stubbornly and repeatedly, has struggled to confirm.