Co-Q10 was part of my supplement package during my year of treatment according to Dr Myhill's protocol. Against advice, I tried tinkering slightly by adding them all one by one, so I could get a sense of which ones had the most beneficial effects, and balance them myself in the longer term - I didn't want to end up on the whole expensive package for life. CoQ10, and even more so B12, seemed the most significant for me.
Anyway, I would echo what others have said about the methylation block, that the variability in response is because different people have different blocks and different deficiencies and so some people can absorb it, others can't, some can tolerate or excrete the toxins released, and others really, really can't, big time.
So my answer, to what's been said, is that while you might get some results by trying B12, or CoQ10, or omega-3 oils, or whatever, really I suspect what you need is a physician who knows what they're doing (and hasn't been struck off for it), as much testing as you can reasonably afford to identify your individual pattern of deficiencies, and then a supplementation programme that's tailored to your individual needs in quite a detailed way.
It's always sad to hear "I tried CoQ10 and it did nothing for me", because it just seems so likely to me that it's just one part of the puzzle, which is an individual thing and has to be treated as such - which seems to be what all the physicians who treat using CoQ10 amongst other supplements are saying.
