topicPostbiotic Sleep Randomized Trial
claimCompared with placebo, SNK improved Sleepiness on Rising ( p = 0.032) and Initiation and Maintenance of Sleep ( p = 0.010).
evidence level2
citationWatanabe T (2025)
sourceEffect of Heat-Killed <i>Lactiplantibacillus plantarum</i> SNK12 on Sleep Quality and Stress-Related Neuroendocrine and Inflammatory Biomarkers in Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Trial.
topicPostbiotic Sleep Randomized Trial
claimHeat-killed Lactiplantibacillus plantarum SNK12 (SNK), isolated from a traditional Japanese fermented food, has been suggested to influence sleep quality, but human data on sleep improvement with heat-killed lactic acid bacteria (postbiotics) remain limited.
evidence level2
citationWatanabe T (2025)
sourceEffect of Heat-Killed <i>Lactiplantibacillus plantarum</i> SNK12 on Sleep Quality and Stress-Related Neuroendocrine and Inflammatory Biomarkers in Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Trial.
topicPostbiotic Sleep Randomized Trial
claimWe conducted a randomized controlled trial to test whether heat-killed SNK (≥1 × 10 11 cells/day for 4 weeks) improves sleep quality and alters stress-related immune and neuroendocrine biomarkers.
evidence level2
citationWatanabe T (2025)
sourceEffect of Heat-Killed <i>Lactiplantibacillus plantarum</i> SNK12 on Sleep Quality and Stress-Related Neuroendocrine and Inflammatory Biomarkers in Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Trial.
topicPostbiotic Sleep Randomized Trial
claim[1] [2] According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), specific criteria must be met to diagnose insomnia, including: (a) Dissatisfaction with sleep duration or quality, including difficulty falling asleep, prolonged sleep, and early awakening, accompanied by associated symptoms.
evidence level3
citationWu Qiong (2026)
sourceInsomnia: the gut microbiome connection, prospects for probiotic and postbiotic therapies, and future directions
topicPostbiotic Sleep Randomized Trial
claimGaining a comprehensive understanding of the neural circuits associated with various chemicals involved in sleep-wake transition is crucial for advancing strategies for managing insomnia.
evidence level3
citationWu Qiong (2026)
sourceInsomnia: the gut microbiome connection, prospects for probiotic and postbiotic therapies, and future directions
topicPostbiotic Sleep Randomized Trial
claimTable 1 Table 1 Sleep regulation factors Receptors Primary sources Findings Melatonin (Mel) 1 2 MTMT Pineal gland 1 2 1 1 [31] [31] [32] [33] [34] [35] [36] [37] MTis associated with the regulation of circadian rhythms and primarily involved in the modulation of REM sleep, whereas selectively promoting NREM sleep.MTincreases non-rapid eye movement (NREM) sleep, while MTregulates rapid eye movement (REM) sleep.
evidence level3
citationWu Qiong (2026)
sourceInsomnia: the gut microbiome connection, prospects for probiotic and postbiotic therapies, and future directions
topicPostbiotic Sleep Randomized Trial
claim(b) The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral or other important areas of functioning.
evidence level3
citationWu Qiong (2026)
sourceInsomnia: the gut microbiome connection, prospects for probiotic and postbiotic therapies, and future directions