I've been taking it for about 6 years (for autoimmune diseases such as Crohn's, PMR and Sjogren's) and I can't say I have experienced any fatigue. I feel very certain that it works for Crohn's. Can't tell about the others. But since I have been symptom and medication free (except for the LDN) I feel pretty good about it. I take just 2 mg- because 4mg didn't make any difference. I say try it carefully. Start with a low dose and work up. And there is lots of research on to look at. Good luck!