Evaluation of the safety of high-dose Lactobacillus gasseri CP2305 supplementation in healthy adults: A randomized, double-blind, placebo-controlled study.

2026-06
Toxicology reports 16

PubMed: 41756348
DOI: 10.1016/j.toxrep.2026.102222

Study Design

Type: Randomized Controlled Trial (RCT)
Sample size: n = 95
Population: 44 who met the eligibility criteria were randomly assigned to either the L. gasseri CP2305 group (n = 22) or the placebo group (n = 22)
Methods: randomized, double-blind, placebo-controlled, parallel-group trial; all participants ingested 20 tablets of either L. gasseri CP2305 or placebo daily for 4 weeks

Objective

Lactobacillus gasseri CP2305 (L. gasseri CP2305) has been reported to exert intestinal regulatory, anti-stress, and sleep-improving effects in healthy adults. This study aimed to evaluate the safety of an excessive intake of L. gasseri CP2305 in a randomized, double-blind, placebo-controlled, parallel-group trial.

Methods

Among 95 participants who provided written informed consent, 44 who met the eligibility criteria were randomly assigned to either the L. gasseri CP2305 group (n = 22) or the placebo group (n = 22). All participants ingested 20 tablets of either L. gasseri CP2305 or placebo daily for 4 weeks. The L. gasseri CP2305 group consumed 1.0 × 10 ¹ ¹ cells of L. gasseri CP2305 cells per day. To assess the safety of CP2305 tablets, physical examinations, hematological and biochemical blood tests, urinalysis, recording of subjective symptoms, and physician interviews were conducted.

Results

One participant was excluded from the analysis; thus, the final analysis included data from 22 participants in the L. gasseri CP2305 group and 21 participants in the placebo group. No adverse clinical findings were observed in either group.

Conclusion

The results of this study demonstrate that no safety concerns were identified in the physical examinations, hematology, blood biochemistry, urinalysis, or subjective symptoms. These findings support the safety of L. gasseri CP2305 tablets even at high-dose intake (1.0 ×10 ¹¹ cells/day).

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Lactobacillus gasseri	—	No Adverse Safety Findings	Neutral	Small	View source No adverse clinical findings were observed in either group... no safety concerns were identified in the physical examinations, hematology, blood biochemistry, urinalysis, or subjective symptoms.