GBL
GBL is a synthetic depressant of the lactone chemical class that functions as a prodrug for GHB1, producing powerful euphoric and disinhibiting effects comparable to alcohol intoxication. It is widely available as an industrial solvent and cleaning agent.1 GBL is a strong acid that corrodes mucous membranes and must be heavily diluted in a non-alcoholic beverage before oral consumption. It also dissolves most plastics, requiring glass or high-density polyethylene containers for storage.
Contents
Dosage & Duration
Dosage
GBL is highly caustic and must be diluted thoroughly in a non-alcoholic liquid before ingestion to avoid injury to the mouth, throat, and stomach lining. Amounts above 2 ml commonly produce deep sedation or unconsciousness. Individual response varies widely; compared with GHB, GBL acts more rapidly and with greater potency, though its effects are shorter-lived. Tolerance to the sedative and hypnotic effects can build quickly with repeated dosing over several days and typically resolves within one to two weeks after discontinuation.
Duration
Subjective Effects
Effects vary widely by individual, dose, and context.
Physical
The physical effects of GBL can be broken down into several components which progressively intensify proportional to dosage.
Cognitive
The cognitive effects of GBL can be broken down into several components which progressively intensify proportional to dosage.
Reagent Testing
Loading reagent data
Pharmacology
Pharmacodynamics
Pharmacokinetics
GBL is rapidly converted to GHB in the blood by paraoxonase (lactonase) enzymes.2 Animals lacking these enzymes exhibit no effects from GBL. Due to its greater lipophilicity compared to GHB, GBL is absorbed more quickly and achieves higher bioavailability, resulting in a faster onset and shorter duration of action.34 Lactonase enzyme levels vary between individuals, which can produce unpredictable responses, particularly in first-time users.3 One milliliter of pure GBL converts to approximately 1.65 grams of sodium GHB equivalent.5
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
GHB, 1,4-Butanediol, Other GABAergic depressants (alcohol, phenibut, baclofen, and other GABA-B agonists)
Harm Potential
Addiction & Dependence
Psychological
HighModerate to high psychological addiction potential with compulsive redosing commonly reported due to the substance's short duration. When consumed in excessive amounts with high frequency dosing, psychological dependence can develop.
Physical
HighPhysical dependence can develop with frequent use, with withdrawal effects reportedly building faster than with GHB and other longer-acting depressants. Withdrawal symptoms range from anxiety, insomnia, and tremors in light to moderate users, to severe symptoms including delirium, psychosis, and hallucinations in heavy users.6 Some users adopt around-the-clock dosing regimes simply to avoid withdrawal.6 Withdrawal severity is comparable to benzodiazepine withdrawal syndrome in prolonged heavy use cases.78
Toxicity
GBL acts as a mucous membrane irritant and solvent, causing esophageal and gastro-intestinal irritation particularly when taken undiluted; stomach discomfort, nausea, and pain are more common with GBL than with GHB.
Chronic administration may impair spatial memory, working memory, and learning; animal studies demonstrated neuronal loss in the hippocampus and prefrontal cortex with repeated dosing, paradoxically showing greater neurotoxicity at lower doses than higher doses.9
Psychosis Risk
Psychosis, delirium, and hallucinations can occur as severe withdrawal symptoms following heavy, prolonged use.68 These psychiatric symptoms are associated with abrupt discontinuation rather than acute intoxication.
Seizure Risk
Seizures can occur at very high doses and during withdrawal from chronic high-dose consumption. GBL is reportedly less prone to causing seizures and convulsions than GHB during intoxication. Uncontrollable muscle twitching at high doses may progress into epileptic seizures. Withdrawal-induced epileptic seizures are documented with abrupt discontinuation of frequent heavy use.
History & Culture
GBL has a long history as an industrial chemical, primarily valued as a solvent and intermediate in the synthesis of other compounds. Its commercial applications have included use as a flavoring agent, stain remover, wheel cleaner, paint stripper, superglue remover, and as a solvent in certain wet…
Legality
International
GBL is not listed under the 1961 Single Convention on Narcotic Drugs. It is not listed under the 1971 Convention on Psychotropic Substances. It is not listed under the 1988 Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances.
By Country
References
Source Pages
Citations
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- Fateh, S. T., & Salehi-Najafabadi, A.. (2022). Repurposing of substances with lactone moiety for the treatment of gamma-Hydroxybutyric acid and gamma-Butyrolactone intoxication through modulating paraoxonase and PPARgamma. Frontiers in Pharmacology, 13, 909460. https://doi.org/10.3389/fphar.2022.909460123
- Goodwin, A. K., Brown, P. R., Jansen, E. E. W., Jakobs, C., Gibson, K. M., & Weerts, E. M.. (2009). Behavioral effects and pharmacokinetics of gamma-hydroxybutyrate (GHB) precursors gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) in baboons. Psychopharmacology (Berl), 204(3), 465-476. https://doi.org/10.1007/s00213-009-1477-8123
- Busardò, F. P., Gottardi, M., Tini, A., Minutillo, A., Sirignano, A., Marinelli, E., & Zaami, S.. (2018). Replacing GHB with GBL in Recreational Settings: A New Trend in Chemsex. Current Drug Metabolism, 19(13), 1080-1085. https://doi.org/10.2174/138920021966618092509083412
- Tini, A., & Del Rio, A.. (2020). Has GBL Replaced GHB in Recreational Settings?. Archives of Industrial Hygiene and Toxicology, 71(2), 167-168. https://doi.org/10.2478/aiht-2020-71-34241
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Further Reading
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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