Effect of melatonin enriched with L-Tryptophan and 5-Hydroxytryptophan on sleep parameters in children with neurodevelopmental disorders

Introduction: Melatonin plays a key role in sleep regulation. Combining melatonin with its precursors, L-tryptophan (LT) and 5-Hydroxytryptophan (5HTP), may influence sleep-related outcomes, but evidence in children with neurodevelopmental disorders (NDDs) is limited. This exploratory study compares the effects of melatonin combined with 5HTP (M-5HTP) and melatonin combined with LT (M-LT) on sleep disorders in children with NDDs. Methods: This single-center, randomized pilot comparative trial involved children under five years of age with NDDs free of sleep-inducing drugs. Baseline evaluations and actigraphy monitoring were performed. Children were randomly assigned to either M-5HTP (1 mg Melatonin +10 mg 5HTP) or M-LT (1 mg Melatonin +20 mg LT) treatment at 8 p.m. for at least four weeks. Post-treatment actigraphy monitoring assessed sleep parameters. Results: Of 51 screened children, 26 were enrolled and 13 completed the study (M-5HTP: 9, M-LT: 4). No statistically significant between-group differences in change scores were observed. Within-group analyses showed a significant reduction in the Sleep Movement Index (SMI) from baseline to follow-up in the M-5HTP group (T0: 6.55; T1: 1.25; p=0.006), whereas no significant changes were observed in the M-LT group. Discussion: In this exploratory pilot study, a within-group reduction in nocturnal motor activity was observed among M-5HTP completers. Given the small sample size, high attrition rate, and limited statistical power, these findings should be interpreted cautiously and considered hypothesis-generating.