Thanks Newport!!! I wish I'd known that several weeks ago when I started the Cysteine program. I had an increase in my chronic fatigue and any and all of my mental symptoms got MUCH worse. I was a mess. It finally dawned on me it might be the Cysteine so I stopped it and it took a/b 10 days to calm things down. I believe you found the answer for me. I'd tested high in heavy metals a few years ago through great smokies labs and mercury was one of the higher ones. Ugh!