I have had a littel bit of acne, nothing major. My chest hurts a bit, I guess from this thread it could be the PG. I cannot comment on sleep because I have a 5 week old daughter who hates to sleep anyways, but I have no issues taking a few drags off the ecig and then trying to pass out for a little while. No muscle cramps of any sort, the plumbing seems to be working as it normally does.