GHB is an industrial solvent, a cleaning chemical people drink.

The confusion starts from a true sentence. The 2000 US law that put GHB in Schedule I found that “If taken for human consumption, common industrial chemicals such as gamma butyrolactone and 1.4-butanediol are swiftly converted by the body into GHB.”[1] The CDC had described GBL a year earlier: “GBL is an industrial and household solvent of acrylate polymers, and unintentional poisonings have been reported”.[2] Retold, the solvent and the drug became one thing.

GHB is a body chemical. A 1997 review of its role in the brain: “gamma-Hydroxybutyrate is a metabolite of GABA which is synthesized and accumulated by neurons in brain”, and “This substance is present in micromolar quantities in all brain regions investigated as well as in several peripheral organs”.[3] A 2015 review: “Trace amounts of GHB are produced endogenously (0.5-1.0 mg/L) in various tissues, including the brain”.[4]

The solvents are real. The World Health Organization's 2014 review says of GBL: “It is a common solvent found in paint strippers, nail polish removers, stain removers and circuit board cleaners.”[5] A 2011 paper on making it: “1,4-Butanediol (BDO) is an important commodity chemical used to manufacture over 2.5 million tons annually of valuable polymers”.[6] Both become GHB once swallowed: 1,4-butanediol “is also rapidly converted to gamma-hydroxybutyric acid by enzymes in the blood and liver of animals and humans”.[7] The 2015 review notes that “Both GBL and BD have cosmetic and industrial applications and are therefore not easy to classify as controlled substances”.[4]

So the bottle in a cleaning aisle can hold the drug's precursor, but the drug itself is not a solvent. That GHB is natural says nothing about its safety either: the same review warns that “The dose-effect curve for GHB is rather steep, which means that small increases in dose cause disproportionate increases in behavioral effects and toxicity.”[4]