4-phenyl-2-dimethylaminotetralin compounds, formulations, and methods are provided for selective modulation of serotonin 5-HT2A and 5-HT2C receptors without causing sedation at doses that are antipsychotic. Mechanisms for selective modulation are shown to involve inverse agonism at one or more of the 5-HT2A-2C receptors based on stereochemistry and substituents. The technology can be targeted to receptors inside or outside the central nervous system.