Exploratory pilot study of a spray-type probiotic delivery system for vaginal health in women at risk for bacterial vaginosis

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Bacterial vaginosis (BV) is a common gynecological condition affecting women of reproductive age, characterized by disruption of vaginal microbiota. Current probiotic interventions, including oral supplements and vaginal suppositories, face limitations in vaginal colonization and user compliance. This study evaluated the preliminary clinical, microbiological, and safety outcomes of a novel spray-type probiotic powder (BalanceTalk Probiotic Feminine Hygiene Powder) containing multiple Lactobacillus strains for BV prevention and treatment. This single-arm exploratory clinical study was conducted at Ewha Womans University Hospital from December 2023 to June 2025. Premenopausal women aged 19–55 years were enrolled and instructed to apply the spray-type probiotic powder (containing L. plantarum , L. rhamnosus , L. paracasei , and L. crispatus ) to underwear or panty liners in contact with the vulvovaginal area once daily for 4 weeks. Primary outcomes included vaginal symptom improvement and Nugent score changes. Secondary outcomes assessed vaginal microbiome composition using 16 S rRNA gene sequencing. Statistical analyses included Wilcoxon signed-rank test, McNemar’s test, and mixed-effects logistic regression. Of 60 enrolled participants, 45 completed the study (75% completion rate). Overall improvement in vaginal symptoms approached statistical significance ( p = 0.051), particularly in the high-risk group (Nugent score ≥ 4; p = 0.020). In the high-risk group ( n = 16), mean Nugent scores decreased significantly from 6.13 to 4.63 ( p < 0.001), with 8 of 16 participants (50.0%) showing a reduction in Nugent score. Lactobacillus abundance was significantly associated with lower Nugent score (OR = 0.077, 95% CI: 0.009–0.634). Alpha diversity indices correlated significantly with Nugent score ( p < 0.05). Beta diversity and overall Lactobacillus abundance showed no significant changes. Three mild adverse events were reported with no serious safety concerns observed. The spray-type probiotic was associated with improvement in vaginal symptoms and reduced Nugent scores, particularly among women with baseline Nugent scores ≥4, with no serious safety concerns observed. The observed negative correlation between Lactobacillus abundance and Nugent score is consistent with the known role of Lactobacillus in maintaining vaginal health, although a causal effect of the intervention cannot be established from this single-arm study. Larger randomized controlled trials are warranted to confirm these findings and establish clinical utility.