Hi, no I don't use MSM currently, but only because I have switched gears and trying to regain my health from finding parasites
almost two years ago. When I did take it, I noticed the benefits of it. I haven't had testing, didn't need it. I started taking raw garlic and the parasites
were evident. Before that I would not have believed it.
The only reason I mentioned it is because the dark circles were one of those odd symptoms I had in the beginning. I had worked hard to get 7-8 hours of natural sleep nightly, as I believe it is the key to staying young and looking youthful, and it was really odd that I seemed to have dark circles when I didn't before. Both MSM and grape seed have properties that could be stirring up parasites. Or it could have no relevance at all in your case. There are many other less freaky reasons for you to have dark circles and brain fog. I hope that is the case for you.