In twenty three years of taking various prescription meds, vitamins and supplements with the aid of an internist and several NDs, taking supplements recommended on various CFS/ME groups, and trying different diets, I have never found anything that helped me at all.
The only reaction that I've ever had from a supplement was from magnesium - it made me so sleepy during the day that I turned into a zombie. However, having said that, I still live in hope of finding something that will relieve some of my CFS symptoms, especially the fatigue and PEM.