Do oral probiotic strains reach the vagina in healthy women?

Detection of Orally Delivered Probiotic Strains in the Vaginal Microbiome of Healthy Female Adults

We will test whether taking oral probiotic supplements leads to those probiotic strains appearing in the vagina of healthy women aged 18 to 50.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 72 (estimated)
• Ages: 18 Years to 50 Years
• Sex: Female
• Sponsor: Lallemand Health Solutions (Industry-sponsored)
• Locations: 1 site (Montreal)
• Trial ID: NCT07246161 on ClinicalTrials.gov

What this trial studies

Healthy women aged 18–50 who stop other probiotic and fiber supplements will take one of three oral probiotic formulas daily for four weeks. Researchers will collect stool samples four times, vaginal swabs at multiple visits, vaginal pH measurements five times, and perineal skin swabs to track whether the probiotic strains appear and persist. The phase 2 interventional design focuses on detecting transit and colonization rather than treating a condition. Molecular and culture-based methods will be used to identify and quantify the probiotic strains in stool, vaginal, and perineal samples.

Who should consider this trial

Good fit: Ideal participants are clinically healthy, non‑menopausal women aged 18–50 with regular menstrual cycles who can discontinue other probiotic and fiber supplements and provide multiple stool, vaginal, and perineal samples.

Not a fit: Women who are menopausal, have abnormal vaginal pH outside the study's allowed range, have irregular cycles, active vaginal infections, or cannot stop other probiotic/fiber products are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the results could show that oral probiotics reach and support the vaginal microbiome, helping guide non-invasive options to maintain vaginal health.

How similar studies have performed: Prior studies have shown that some oral probiotics can influence the vaginal microbiome in certain women, but results are mixed and direct evidence of strain transit to the vagina remains limited.

Eligibility criteria

Inclusion Criteria:

* Clinically healthy female between the ages of 18 and 50 years, inclusive,
* have a regular or predictable menstrual cycle
* Typically have regular bowel movements,
* Willing and able to consume a probiotic supplement for 4 weeks,
* Willing to discontinue consumption of probiotic supplement and probiotic-fortified products 2 weeks before the start of the study and throughout the study,
* Willing to discontinue fiber supplements 2 weeks before the start of the study, and throughout the study,
* Willing to provide 1 stool sample 4 times throughout the study,
* Willing to provide 2 vaginal swabs 4 times throughout the study,
* Willing to undergo vaginal pH swab measurements (with a swab) 5 times throughout the study,
* Willing to provide 2 perineal skin swabs (skin between the vagina and the anus) 3 times throughout the study,
* Willing to complete a pregnancy test at the screening visit.

Exclusion Criteria:

* Menopausal women,
* Vaginal pH \< 2 or \> 5 measured at screening,

  •. Menstruation during the sample collection times,
* Women that are lactating, pregnant, attempting to get pregnant, or have a positive pregnancy test,
* Use of vaginal probiotics in the last 3 months,
* Use of local vaginal antibiotics or antifungals in the last 3 months.
* Use of oral antibiotics or antifungals in the last month,
* Ongoing symptoms of vaginal and/or urinary tract infections,
* Current treatment for vaginal sepsis or urosepsis,
* Currently being treated for a severe chronic disease (e.g. cancer, renal failure, chronic inflammatory digestive or gastro-intestinal disease, immunodeficiency, etc.),
* Clinical diagnosis of a gynecological disease or condition (e.g, fibroma, endometriosis, polycystic ovarian syndrome, etc.),
* Clinical diagnosis of secondary dysmenorrhea,
* Intolerance, allergy or sensitivity to milk, soy, or yeast.

Where this trial is running

Montreal

• Evalulab — Montreal, Canada (Recruiting)

Study contacts

• Study coordinator: Jenna Bouassaly, MSc

Conditions Focus is on Healthy Subjects; Probiotics; Women's Health