GBL ( gamma-Butyrolactone or γ-Butyrolactone) is a hygroscopic colorless, water-miscible liquid with a weak characteristic odor. It is the simplest 4-carbon lactone. It is mainly used as an intermediate in the production of other chemicals, e.g. methyl-2-pyrrolidone. GBL is a liquid with a chemical smell and taste. GBL is a precursor to GHB, which means that it is converted to GHB inside your body after swallowing. It has a faster onset of action than GHB, and is often more potent – so a smaller dose is required to have the same effect.
Gamma-Butyrolactone (GBL) has widespread industrial use. It is a common solvent found in paint strippers, nail polish removers, stain removers and circuit board cleaners. It is also a common intermediate in industrial chemistry including the manufacture of pyrrolidones and in some pharmaceuticals.
GBL is often used with other drugs, particularly cannabis, alcohol and ecstasy. GBL has the capacity to produce a state of dependence, and can produce similar effects as GHB.