Probiotic yeast shown to support vaginal health in recent study

November 8, 2019

A new clinical study demonstrated the ability of the probiotic yeast strain Saccharomyces cerevisiae CNCM I-3856 from Gnosis by Lesaffre (Milan, Italy) — branded Quatreflora — to support vaginal health in women. The results were presented during Probiota Americas 2019 in Vancouver, Canada and has not yet been published.

In the study, 60 healthy women of childbearing age, with regular menstrual cycles, normal vaginal flora, normal vaginal pH, and the same efficient contraception method for at least three months, were given either 500 mg per day (2.5x109 CFU), 1000 mg per day (5x109 CFU), or placebo. After four weeks of daily oral supplementation, vaginal samples showed that the migration of probiotics from the intestine to the vagina occurred in 21% of subjects taking 500 mg daily, 16% of subjects taking 1000 mg daily, and in zero subjects from the placebo group. This proportion is comparable to what was observed in previous studies with lactobacilli probiotics, in which 25% of women had the probiotic in vaginal microbiota after four weeks of supplementation.1 The study also shows that the probiotic survives through the gastrointestinal tract, finding its way into the stool of 80% of subjects taking 500 mg daily, and in 100% of subjects taking 1000 mg daily.

“As far as we know, the migration of a probiotic yeast from rectum to vagina has never been described before our pilot clinical study” said Silvia Pisoni, marketing manager of Gnosis by Lesaffre, in a statement. “Probiotics are very promising candidates in preventing or restoring the imbalance of the vaginal microbiota. According to the findings of the trial we really believe Quatreflora may contribute to the delicate women’s health.”


1. Kovachev S et al. “Effect of Lactobacillus casei var rhamnosus (Gynophilus) in restoring the vaginal flora by female patients with bacterial vaginosis – randomized, open clinical trial.” Akusherstvo Ginekologiia (Sofiia), vol 52, no 1 (2013): 48–53