Gene Tonics are special serums made from processed ADAM that introduce modified stem cells into the body, allowing for genetic modification and mutation, giving the user what some might call "super powers". While active Plasmids require EVE for use, Tonics provide an effect merely by being equipped. Tonics are powerful, but excessive use of them leads to physical and mental addiction and instability. This was a major factor in the eventual downfall of Rapture society.