Purpose <p>Real-world data on the orexin receptor antagonist lemborexant in younger populations with insomnia are scarce. This retrospective observational study aimed to evaluate the real-world effectiveness and safety profile of lemborexant in a predominantly younger cohort of adults treated via online consultations.</p> Methods <p>We retrospectively analyzed medical records from patients aged ≥ 18 years treated at the Wellness General Clinic between April 2022 and August 2024. The Athens Insomnia Scale (AIS) was used to evaluate the effect of lemborexant. The primary endpoint was the change in AIS total score from the first visit to final follow-up, evaluated by paired t-test. Changes over time were assessed via a linear mixed-effects model. Responders were predefined as achieving AIS ≤ 5, evaluated by McNemar’s test.</p> Results <p>A total of 382 patients (mean age, 34.3 ± 9.8 years; male/female = 189/193) were included. Treatment with lemborexant was associated with a significant improvement in AIS total score from 11.9 ± 4.6 at the first visit to 5.9 ± 4.1 at the final follow-up (Δ = − 5.9; <i>P</i> &lt; 0.001; Cohen’s d = 1.20). Linear mixed-effects modelling confirmed a significant Time effect (all <i>P</i> &lt; 0.001). Responder rate rose from 7.6 to 50.3% (<i>P</i> &lt; 0.001).</p> Conclusions <p>In this retrospective analysis of a real-world, young-adult cohort treated via online consultations, lemborexant use was associated with a marked improvement in insomnia symptoms. These findings extend the evidence base for lemborexant, but prospective, randomized controlled trials are needed to confirm these results and establish causal efficacy.</p>