One time I used GBL 2 weeks 24/h, the doses were always the same starting the day with 1,5ml and then every hour boosting with 0.5,. The tolerance never did rise. Ive tried this many times one time I did it for one week and no tolerance rise. I know long time addicts might take 2ml every hour, but still, I think the tolerance rise is very slow on GBL, is there some kind of explanation?