I'm under the impression that GHB is healthier than GBL is this true? I also heard that you need less GHB to get the same effects than GBL, in other words GHB is more potent than GBL is this true? Why is GBL more unhealthy?
GBL is considered by some to be more harmful- although there is little evidence for this. The 'Lactone' part of the molecule makes some people a bit nervous. There is low level evidence for an increase in acidosis - but this is not replicated in vivo.
GHB is a powder and GBL is a liquid. Typical doses are something like 2.5grams of GHB or 2ml of GBL.
This is the reason ghb has such a bad rep. Noone knows the concentration, then someone od's. You need to evaporate the liquid then weigh out the powder.