Aloysia citrodora (Lemon Verbena) and Sleep Regulation: Phytochemical Constituents, Molecular Mechanisms, Preclinical and Clinical Evidence, and Translational Perspectives

Aloysia citrodora (lemon verbena) is traditionally used to promote relaxation and sleep, but its clinical efficacy and underlying mechanisms remain uncertain. This narrative review critically evaluates its phytochemical constituents, potential sleep-regulatory mechanisms, preclinical and clinical evidence, pharmacokinetics, safety, and translational challenges. Literature published through 16 October 2026 was identified through PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar, supplemented by trial registries, regulatory documents, and reference screening. Evidence was qualitatively synthesized using methodological principles informed by SANRA and PRISMA-S. Aloysia citrodora contains phenylethanoid glycosides, particularly verbascoside, flavonoids, and volatile terpenoids. Preclinical investigations suggest sedative and sleep-modulating effects, with GABAergic and adenosinergic signaling representing plausible but incompletely validated mechanisms. Randomized clinical trials report improvements in subjective sleep quality and selected sleep-continuity parameters. However, objective improvements are modest, findings are heterogeneous, and human polysomnographic evidence is unavailable. Limited independent replication, uncertain systemic and central nervous system exposure, and insufficient long-term safety data restrict clinical interpretation. Aloysia citrodora may offer complementary benefits for selected sleep complaints, but evidence remains insufficient to establish efficacy for chronic insomnia. Independent, adequately powered trials using standardized preparations, prespecified clinically meaningful outcomes, objective sleep assessments, and integrated pharmacokinetic and safety evaluations are needed before broader clinical recommendations can be supported.