Hair samples from two healthy teenagers were sent under assumed names to 13 commercial laboratories performing multimineral hair analysis. The reported levels of most minerals varied considerably between identical samples sent to the same laboratory and from laboratory to laboratory. The laboratories also disagreed about what was "normal" or "usual" for many of the minerals. Most reports contained computerized interpretations that were voluminous, bizarre, and potentially frightening to patients. Six laboratories recommended food supplements, but the types and amounts varied widely from report to report and from laboratory to laboratory. Literature from most of the laboratories suggested that their reports were useful in managing a wide variety of diseases and supposed nutrient imbalances. However, commercial use of hair analysis in this manner is unscientific, economically wasteful, and probably illegal.