Anatomology Serotonin Molecular Structure Earrings by Anatomology. $18.00. Sterling silver ear wires. Earrings come in velvet glass top box with informational card. Serotonin is a brain chemical that is associated with mood and sleep. Many anti-depressants work by elevating levels of serotonin. Measures 0.5" width by 0.8" height.. Save 25%!