I am convinced this supplement works for depression and fatigue. I have taken 400 mg twice a day and can definitely feel a difference the first day. Something else that I have noticed is that my hairy leukoplakia goes away within days. It can also decrease liver enzymes. However, it is contraindicated for those with bipolar disorder. It is not cheap. I get mine from Jarrow at the Houston Buyers Club.
Here is a summary of studies
I am attaching a study done in HIV