My understand is that it protects liver cells from toxins and helps regenerate cells. So, the benefit is at the molecular level. I don't think there is any way in the world you would get stones from milk thistle. I have been taking at night before bed since the liver does most of its work between 1 and 4 AM. I have been taking it everyday for a month now. I did initially notice a surge of energy in the first week which could be related to improved metabolic activity in liver cells.