The probiotic strain, marketed as Gyntima Balance outside the United States, improved the microbial balance, shifting from troublesome Community State Types associated with dysbiosis toward Lactobacillus-dominated vaginotypes.
“This is a crucial distinction: The product doesn’t just alter the composition slightly, it promotes a complete change in the type of vaginal microbiota to one that is clinically recognized as healthy,” Dr. Marta Pérez, lead researcher and R&D manager at AB-Biotics, told NutraIngredients.
“This result provides robust clinical evidence for the efficacy of a specifically selected oral probiotic for vaginal health. It validates the oral-gut-vagina axis by confirming that the probiotic can survive gastrointestinal transit and successfully colonize the vagina, providing women with a convenient and scientifically proven tool for proactively supporting their vaginal microbiome.”
Dr. Perez noted that the mechanisms allowing L. gasseri KABP 064 to colonize the vagina have been well-characterized in preclinical in vitro studies, demonstrating its strong resistance to gastrointestinal and vaginal conditions, as well as a high capacity to adhere to vaginal epithelial cells.
Furthermore, the probiotic produces significant amounts of lactic acid, which contributes to maintaining a healthy, low vaginal pH, she added, noting that the strain has also shown potent antagonistic activity against over 100 urogenital pathogens.
Addressing vaginal dysbiosis
Research suggests that vaginal dysbiosis is associated with gynecological conditions such as bacterial vaginosis (BV), endometriosis, polycystic ovary syndrome (PCOS) and pregnancy complications.
Most studies on modulating vaginal dysbiosis have involved oral probiotics. Oral administration requires that the probiotics survive the harsh conditions of the gastrointestinal tract so that they can colonize the vagina via the gut-vagina axis.
Additionally, some research suggests that the mucosal membranes may reject probiotics, thereby preventing them from colonizing. This may be because the body sees them as alien to its own microbiota and local immunity.
An alternative approach known as autoprobiotic technology or personalized symbiont therapy (PERST) has gained attention from researchers. This involves isolating bacterial strains from a person’s own microbiota, checking for the absence of genes associated with pathogenicity, cultivating the beneficial bacteria and returning them to the host.
Because this approach avoids the body rejecting the bacteria, it is often successful in treating conditions such as bacterial vaginosis (BV). However, autoprobiotic technology is not readily available, and thus, researchers are investigating ways to modulate vaginal bacteria using commercially available technologies.
Study details
The first part of the study involved an in vitro screening of 45 strains of the species L. gasseri and L. crispatus, isolated from the vaginal tracts of healthy women and belonging to the bacterial collection of Kaneka Corporation.
The researchers assessed the bacteria’s ability to withstand simulated gastrointestinal and vaginal conditions and to colonize the vagina.
“Lactobacillus gasseri CECT 30648 (Lg) and Lactobacillus crispatus CECT 30647 (Lc) showed excellent in vitro attributes, including antagonism against 10 urogenital pathogens, resistance to gastrointestinal tract and vaginal environment—including high concentrations of biogenic amines—and adhesion to vaginal epithelium,” the researchers wrote.
In the next part of the study, 48 healthy premenopausal women between the ages of 18 and 45 were randomly assigned a daily capsule containing Lg (109 CFU), a combination of Lg plus Lc (1.5 ×109 CFU ) or a placebo for up to 18 days between menstrual cycles. They had vaginal samples collected every three days.
The results revealed that Lg, but not Lc, was detected in 55.9% of participants in the active groups. Furthermore, the probiotics were well tolerated.
Although the participants were healthy and asymptomatic, several had vaginotypes that are associated with microbial imbalance. At the end of the study, the vaginotype distribution remained unchanged. Lactobacillus dominated in the placebo group, but the probiotic group had improved, indicating a positive transition towards healthier, Lactobacilli-dominated vaginotypes.
Dr. Perez noted that there is strong potential for L. gasseri CECT 30648 to support gynecological disorders linked to dysbiosis, and the logical step is to conduct further randomized controlled trials in specific study populations.
“This includes women with recurrent BV, aerobic vaginitis or vulvovaginal candidiasis, as well as investigating its potential to improve fertility and conception outcomes in women trying to conceive,” she said.
Source: Microbiol Spectr. 2025 Aug 7;13(9):e00211-25. doi: 10.1128/ spectrum.00211-25. “Lactobacillus gasseri CECT 30648 shows probiotic characteristics and colonizes the vagina of healthy women after oral administration”. Authors: Marta Pérez et al.
