BACKGROUND: (black cumin, or black seed) is popularly known as the seed of blessings in the Arab system of medicine. Though not widely recommended for sleep, a unique proprietary black cumin extract (BlaQmax®/ThymoDream™; BCO-5) has been shown to be helpful in the management of stress and sleep issues. METHODS: This randomized, double-blind, placebo-controlled trial aimed to investigate the efficacy of BCO-5 on the sleep quality of volunteers characterized with a self-reported non-restorative sleep disorder. Healthy male and female participants ( = 70), aged 18-65 years (BMI 22-28 Kg/m) were randomized to either placebo or BCO-5 ( = 35/group). Both interventions were supplemented at 200 mg/day for seven days. Actigraphy and a validated restorative sleep questionnaire (RSQ-W) were used to monitor the influence of BCO-5 on sleep. RESULTS: Compared to placebo, BCO-5 significantly improved sleep quality, as evidenced by both intra-group and inter-group analyses of the actigraphy data. The relative improvements observed were sleep efficiency (7.8%,  < 0.001), total sleep time (19.1%,  < 0.001), sleep onset latency (35.4%;  < 0.001), and wake-after-sleep-onset (22.5%;  < 0.001) compared with placebo. BCO-5 also improved sleep by 75.3% compared to baseline ( < 0.001) and by 68.9% compared to placebo ( < 0.001), when monitored by RSQ-W. BCO-5 was well-tolerated with no reports of side effects or toxicity. CONCLUSION: BCO-5 significantly improved non-restorative sleep in seven days, indicating its potential role as a natural sleep aid.