I know only one thing...when I get in a stress situation, dopamine seems to hit bottom and I can get symptoms (hand tremor or sometimes just hand restlessness or leg restlessness , or my singing voice is gone ) when a couple minutes before I was perfectly ok. I think Rhodiola is helping this though. I was in a stressful situation today and faced it with relative calmness and without symptoms..still haven't taken fava tincture today. COOL (very cool with the temps below freezing all day and having to go out)