Sleep disturbances are widespread in modern societies and linked to a variety of diseases, creating an urgent need for the development of products that help combat sleep difficulties. One suitable nutritional supplement may be a fish hydrolysate composed of low molecular weight peptides. This two-arm, double-blind, randomized, placebo-controlled crossover study investigated the effect of a 4-week fish hydrolysate intervention on sleep in a healthy German population reporting poor sleep quality, assessed with the Pittsburgh Sleep Quality Index (PSQI). Further sleep parameters were measured using an online diary and a wrist wearable device. Additionally, questionnaires related to stress, anxiety, depression, and well-being were evaluated and salivary cortisol and product satisfaction were assessed. The 4-week fish hydrolysate supplementation significantly improved subjective sleep quality measured with the PSQI-score (p = .002). Moreover, individuals reported improvements in sleep efficacy and a reduction in sleep disturbances and daytime sleepiness during fish hydrolysate intake (p = .013, p = .046, p = .004 respectively), but not during placebo phase (all p > .05). No significant intra-individual differences were found between fish hydrolysate and placebo supplementation (p > .05). Although no significant intra-individual differences were found between fish hydrolysate and placebo supplementation, the significant improvement in subjective sleep quality from baseline to treatment phase suggests that fish hydrolysate is a safe nutritional supplement to support individuals with self-reported sleep problems. The study is registered at ClinicalTrials.gov with the Identifier NCT04983355.

Purpose: Insufficient sleep is common and under-reported, linked to increased health risks. Many individuals seek alternatives to conventional medications, which often have adverse side effects. Patients and Methods: This monocentric, single-arm, open-label exploratory study (Reg. No: NCT05748574) evaluated a granulate formulation containing 75 mg extract of the fresh herb of Lactuca sativa, 190 mg Melissa officinalis,120 mg L-Tryptophan, and 60 mg Magnesium in healthy adults with sleep disturbances. Conducted in Germany in 2023, 50 subjects consumed the formula nightly for 14 days. Outcomes were assessed via diaries, questionnaires, cognitive tests, wearables, saliva samples, and polysomnography (PSG) in a 10-subject subgroup. Statistical analysis compared pre- and post-treatment differences. Results: Nightly awakenings reduced by 31% (p < 0.001) and early morning awakenings by 16% (p < 0.001). PSG data indicated a 28% increase in deep sleep (N3&N4, p > 0.05), a 70% rise in stage N4 (p = 0.042) and an 18% reduction in REM sleep (p > 0.05). The Apnea-Hypopnea index decreased by 26% (p = 0.11). Sleep quality (“Sleep questionnaire” SF-B/R index, primary outcome) improved by 14% (p = 0.003), with a 37% improvement in highly anxious individuals (p ≤ 0.001). Restedness increased by 22% in week 1 and 28% in week 2 (p ≤ 0.001). Psychological tension dropped by 21% and up to 29% (p ≤ 0.001). Daytime performance indicators included a 13% reduction in sleepiness and a 23% improvement in mood (p ≤ 0.014). Executive function showed a 13% improvement (p ≤ 0.001) on computerized tests (COMPASS). Findings from wearables, sleep quantity, and salivary biomarkers yielded an inconsistent picture. Adherence was high, with no serious adverse events reported. Conclusion: The formulation was associated with observed improvements in subjective sleep quality—particularly among anxious individuals—as well as well-being and daytime function. Further confirmation through randomized placebo-controlled studies is warranted to further prove causality.