hmm, lets see...
if you dont know the concentration be very careful
a good starting dose for ghb=1.5gr. you can always build up but wait at least half an hour before you take a second dose (this dose should never be more than 50% of the first dose)
like i said, when you dont know the concentration its hard to know how much you ingested...and with ghb you dont want to take too much
you will feel like shit for 2 hours or so, you might puke and basically all you want to do is lay down, close your eyes and sleep...
if you dont take too much youre in for some fun: medium euphoria, relaxation, you become talkative...this thing is great for comedowns
hardly any negative aftereffects at all even when you take a loittle bit too much (actually no negative aftereffects for me)
when you take it in the evening you might wake up at night not being able to fall asleep again (dopamine rebound effect). just take some more and youll be fine
well, thats about it...most important thing to remember is your dose...just start low and build up from there.