After looking into it, I also decided to give it a try. I would assume my mitochondria as being in relatively good shape after a couple years of low-carb eating. My energy levels were fine, I didn't have any brain fog, so no real reason to try it other than just general curiosity.
I started at what the bottle described as 20mg (8 drops). After 15 minutes, I didn't feel at all well. Flushed, maybe even feverish, a little itchy, and just generally ill. That went away after an hour or so, gradually. I think I did the same thing for a few days with similar results, before deciding to halve my dose. Even at 10mg, I still feel it, but it is only mildly unpleasant. I may halve it again.
I haven't noticed extra energy or mental clarity. I'm hoping that even at a low dose, I may get some of the positive cellular effects.
While I was at it, I also got an iodone supplement. Even living coastally, I figured a little extra wouldn't hurt since I no longer use iodized salt. For both of them, I will likely finish the bottle, then take 6 months to a year off before trying them again, if I then decide to bother.
Did you find you needed more than the label suggested, or less as I discovered? Also, have you seen anything about combining MB with DMSO? Just curious.