flobbest, I've noticed no effects in the 2 days I've taken it. The only things I notice are that I like the taste, and my mouth or lips seem to itch after I take it - not enough to conclude its an allergy though.
About sleep... when people report they have more vivd dreams (from any substance) I think it's incorrect to conclude they are having better sleep. If dreams are better remembered it could be that you're having less slow wave sleep, and therefore worse sleep. As someone who has a lot of trouble with daytime mental fatigue and fragmented nighttime sleep, I'm always hoping for something that helps. I'll be sure to report any effects in this area. But I'm not holding my breath.
One final thing, isn't one of the purported benefits of brewer's yeast (and by extension Diamond V) vitamin B-21? B12 supplementation is frequently recommended to improve fatigue or sleep. So, it might be worth comparing this product to B12 (sublingual) to see which is actually working, if any. In my case, although my B12 level was low, supplementation did not help with fatigue.
Mouser, I was thinking the same thing about the frequency of "remembered dreams" noted by several posters. Having suffered from insomnia for about a decade now I have educated myself on the subject of sleep, or lack there of. However, like many, I'm willing to try most anything to achieve the elusive slumber that some fortunate souls enjoy (like my sleeping log wife).
I revieved my Diamond XPC from ebay yesterday, Feb 19th. It smells just like the feed store. I'll post results in a couple of weeks. Over......Frank.