Recent trends in the analysis of GHB in hair

Hair analysis is a valuable tool in forensic toxicology, providing extended detection windows and critical insights into drug testing, usage trends, and drug-facilitated crimes. This systematic review was conducted using Scopus, Web of Science, and PubMed databases from March 2017 to September 2024, and evaluated 19 studies (16 research articles and 3 case reports) on the detection of γ-hydroxybutyrate (GHB) in hair. This review examines recent studies on GHB concentrations in hair, focusing on both endogenous and exogenous concentrations resulting from illicit and prescribed use, as well as the analytical methods employed. This review includes decontamination parameters, extraction techniques, and sample sizes used during the analytical method. New studies report that endogenous GHB levels range from 0.2 to 5.5 ng/mg, while exogenous levels vary widely from 0.3 to 239.6 ng/mg. Additionally, published results indicate that the frequency of use may be more significant than the dosage for exogenous GHB to be incorporated into the hair. A novel adjacent segmentation method has been proposed to differentiate endogenous from exogenous GHB, identifying local peaks within adjacent hair segments. Research into GHB-glucuronide as a biomarker has found it unreliable due to inconsistent correlations with exogenous use. Further research is needed to refine the interpretation of GHB levels in forensic applications.