Combined NY1301 and DDMP on Sleep and Autonomic Function in Summer: A Randomized Clinical Trial
Lead
As summer temperatures climb, so do complaints of poor sleep and daytime fatigue. Many people turn to dietary supplements for relief, but the evidence behind them is often thin. A new randomized controlled trial tests whether a beverage containing the probiotic Lactiplantibacillus plantarum NY1301 combined with the antioxidant DDMP can improve sleep, fatigue, and autonomic function during the hot summer months. The results tell a more cautious story than the marketing might suggest.
What they found
The trial was a double-blind, placebo-controlled, parallel-group study involving 171 healthy adults in Japan. Participants were randomly assigned to drink either a test beverage containing NY1301 plus DDMP or a placebo beverage once daily for eight weeks during the summer season. The researchers measured fatigue, sleep quality, and heart rate variability (HRV) as indicators of autonomic nervous system function.
The primary outcome was a daily log of fatigue severity. On this measure, the supplement failed to outperform placebo. The difference between groups was not statistically significant, meaning the main question the trial set out to answer came back negative.
However, the secondary and exploratory analyses yielded some signals worth noting. At week eight, participants in the supplement group reported falling asleep roughly two minutes faster than those in the placebo group, a difference that was statistically significant (mean difference 2.07 minutes, 95% CI 3.96 to 0.17, p = 0.033). They also reported lower pre-task fatigue on a visual analog scale (mean difference 6.79, 95% CI 13.6 to 0.3, p = 0.047).
Heart rate variability data showed a pattern of improved autonomic recovery. During a mental arithmetic stress task, the supplement group showed a greater increase in the LF/HF ratio, which reflects sympathetic activation. During recovery, they showed a greater decrease in LF/HF and a greater increase in HF power, a marker of parasympathetic activity. These findings suggest the supplement may help the nervous system shift from a stressed to a relaxed state more efficiently.
An exploratory analysis also found that the usual rise in nocturnal respiratory rate associated with higher nighttime temperatures was blunted in the supplement group, indicated by a significant group-by-temperature interaction. This could have implications for sleep quality in hot weather.
Why it matters
Heat stress is known to disrupt sleep by interfering with the body’s natural cooling processes and autonomic regulation. Poor sleep during summer is not just an inconvenience; it can impair cognitive performance, mood, and physical recovery. If a safe, food-grade supplement could meaningfully improve sleep onset or help the body bounce back from stress, that would be a genuinely useful tool.
The autonomic findings are particularly interesting. HRV is a well-established indicator of how well the body adapts to stress. A pattern of stronger sympathetic response during a challenge and faster parasympathetic recovery afterward is generally considered a sign of healthy autonomic flexibility. The fact that the supplement group showed this pattern, even in a modest way, points to a plausible mechanism by which NY1301 and DDMP might exert their effects. The probiotic strain NY1301 has been studied for gut-brain axis effects, and DDMP is known for antioxidant properties that could buffer oxidative stress from heat exposure.
Still, the clinical relevance of a two-minute improvement in sleep onset is debatable. Most people would not notice a two-minute change in how long it takes them to fall asleep. The fatigue improvement, while statistically significant, was modest in magnitude.
Limits
This study has several important limitations. The primary outcome was null, which means the secondary findings must be interpreted with caution. In clinical trials, when the main endpoint does not reach significance, positive results in secondary analyses are considered hypothesis-generating rather than confirmatory. They need to be replicated in a study designed specifically to test those outcomes.
The sample was limited to healthy Japanese adults, which limits generalizability to other populations, including people with clinical sleep disorders. The study was conducted during a single summer, so seasonal variability and longer-term effects were not assessed. The sponsor, Nissin York Co., Ltd., supplied the test beverage and was involved in the study; several authors disclosed affiliation with the sponsor. While the trial was randomized and double-blind, industry-funded research can carry subtle biases in design, analysis, or interpretation.
The autonomic measures, while suggestive, were exploratory. Multiple comparisons increase the risk of false positive findings, and the authors did not adjust for them. The two-minute improvement in sleep onset, while statistically significant, falls well below what is generally considered clinically meaningful, which is typically in the range of 10 to 15 minutes.
Bottom line
This eight-week randomized trial found that a beverage containing NY1301 probiotic and DDMP antioxidant did not significantly reduce overall fatigue, its primary endpoint, in healthy adults during summer. Secondary analyses suggested modest benefits for sleep onset latency, pre-task fatigue, and autonomic recovery, particularly in HRV responses to stress. An exploratory finding that the supplement attenuated temperature-related increases in nighttime breathing rate is interesting but requires confirmation. The autonomic data provide a plausible mechanism and direction for future research, but the clinical significance of the observed effects is uncertain. As it stands, the evidence does not support recommending this supplement for sleep or fatigue management, though it may warrant further investigation in targeted populations.
Source
Tomizawa M, Sugimoto T, Fukao M. Combined NY1301 and DDMP on Sleep and Autonomic Function in Summer: A Randomized Clinical Trial. Journal of Clinical Medicine. 2026;15(11):4175. doi:10.3390/jcm15114175. PMID: 42279036. Funding: Nissin York Co., Ltd.