Population surveys have found a consistently high prevalence of sleep difficulties across Asia. For instance, 47% of the general population in Taiwan, 39% in Hong Kong, 26 to 31% in Japan, and 28% in Singapore reported poor sleep quality.
In a recently published randomized, double-blind, placebo-controlled trial, hydrolyzed chicken extract (ProBeptigen) was shown to improve short-term, long-term, and working memory in middle-aged adults.
A proof-of-concept secondary analysis of data from this trial was conducted in Taiwan to examine whether the sleep quality of the participants improved upon a four-week consumption of ProBeptigen.
Data from 52 healthy subjects aged between 35 and 65 years old with poor baseline sleep quality—Pittsburgh Sleep Quality Index (PSQI) score of greater than 5— were analyzed in the current study funded by Suntory Beverage & Food Asia.
The participants were randomly assigned to receive either 670mg of ProBeptigen or a placebo daily.
Following four weeks of intervention, changes in PSQI global scores did not significantly differ between the two groups. However, the improvement in the subjective sleep quality component score was significantly greater in the ProBeptigen group compared to the placebo group (p = 0.006).
Additionally, participants who consumed ProBeptigen exhibited a numerically greater improvement in daytime function than those who took placebo, although this difference did not reach statistical significance (p = 0.064).
While other PSQI domains did not show statistically significant differences, potentially due to the limited sample size, the good safety profile and the improvement of memory reported in the first study indicate that ProBeptigen could be considered as a complementary approach within a multifaceted sleep management strategy.
“This study suggests that hydrolyzed chicken extract may improve perceived sleep quality, as reflected in PSQI component scores, among healthy adults with poor baseline sleep,” the researchers wrote in Frontiers in Nutrition.
“Although no significant between-group differences emerged for PSQI global scores, improvements in specific components are encouraging and support further evaluation in larger, adequately powered trials. ProBeptigen may serve as a supportive nutritional supplement within a broader, multi-pronged strategy for managing sleep health.”
Mechanisms to be elucidated
The findings in this secondary analysis align with previous data on protein hydrolysates.
In a trial with Japanese participants suffering from insomnia, bovine alpha-S1 casein tryptic hydrolysate raised PSQI global score and subjective sleep quality component score after two weeks, and sleep latency and daytime function after four weeks.
Similarly, a four-week study in Korean participants showed improvements in PSQI global score, and daytime functioning measured by the Epworth Sleepiness Scale.
Another study in a healthy German population found that four-week fish hydrolysate supplementation also significantly enhanced the PSQI global score, and component scores for subjective sleep quality, sleep efficacy, sleep disturbances, and daytime functioning.
Nevertheless, it is important to note that none of these studies found statistically significant differences between the supplement and placebo groups.
The present study demonstrated a larger, statistically significant between-group difference (-0.438 points), suggesting that specific bioactive constituents in hydrolyzed chicken extract may contribute to a comparatively stronger improvement in perceived sleep quality.
“The exact bioactives and mechanisms by which ProBeptigen affects sleep quality remain unclear. It contains various diketopiperazines produced through enzymatic and thermal treatments, and prior in vivo studies suggest that certain diketopiperazines may influence neurotransmitter systems such as GABAergic signaling or exhibit sedative effects,” the authors said.
In addition, ProBeptigen contains tryptophan, a biochemical precursor of serotonin and melatonin, both of which are involved in well-characterized sleep regulatory pathways.
As these mechanistic pathways were not directly assessed in this study, further research is needed to clarify these hypotheses and identify the biological processes through which ProBeptigen may influence sleep, as well as evaluate alternative dosing schedules, include larger sample sizes, and incorporate objective sleep measures.
Source: Frontiers in Nutrition. doi: 10.3389/fnut.2026.1790576. “Hydrolyzed chicken extract (ProBeptigen) on sleep quality in healthy individuals: a secondary analysis of PSQI global and component scores from a randomized double-blind trial”. Authors: Lee Cheng Phua, et al.
