Basically a decoupler that makes your body use up its energy. Leads to raised body temperature, insane sweating and apparently incurable lethargy.
PGCL is kind of a shady substance. I wouldn't trust anything you hear from the companies selling it. It seems based on user feedback to just be a laxative on steroids.
As FF has stated, the info on PGCL is very limited. I find the writeup Albeef did to be the most informative. As far as hard facts scientifically researched on pcgl...good luck finding that.