While much of the evidence for using probiotics for vaginal health is inconclusive, some studies have had promising results.

Humans depend on “good” bacteria in the body to help with a wide range of functions, including digestion, disease prevention, and wound healing. Some of these helpful bacteria are in the vagina, where people may refer to them as the vaginal flora or microbiome.

Most of the time, the body maintains healthy levels of good bacteria so that the good and bad bacteria balance each other out.

However, illness, antibiotics, and other stressors can disrupt the balance, resulting in infections and other health challenges. Probiotics can help restore the balance.

To date, the evidence for using probiotics for vaginal health is inconclusive, but some studies have produced promising results. Probiotics are living organisms that are present in some fermented foods. People can also find them in nutritional supplements.

They may help treat people with gastrointestinal disorders, and may also be beneficial for diarrhea, periodontal disease, and other conditions.

People use probiotics most often to address:

  • Vulvovaginal candidiasis (VVC): Better known as a yeast infection, experts say that 7 in 10 women will experience at least one episode of VVC in their life.
  • Bacterial vaginosis (BV): BV is the most common vaginal condition in females aged 15–44. BV may be linked to bacteria such as Gardnerella vaginalis or occur when Prevotella bacteria outnumber Lactobacillus.
  • Pregnancy health: While researchers have found no evidence that probiotics improve health outcomes for pregnant women or fetuses, they estimate that 1 in 7 women in the Netherlands take probiotic supplements during pregnancy.

Some people also suggest that probiotics can help address the following health challenges:

  • urinary tract infections
  • the spread of sexually transmitted infections
  • the risk of relapse of VVC and BV after treatment with antibiotics

Very few scientific studies have explored the effectiveness of probiotics for vaginal health, however.

One report found that probiotics led to short-term improvements and reduced risk of 1-month relapse for females with yeast infections but did not affect long-term cure rates.

A 2013 study of females with BV found that treatment with oral probiotics in combination with antibiotics resulted in a lower recurrence rate than antibiotics alone. However, a 2019 review of studies found no conclusive evidence that probiotics are helpful for treating BV.

Multiple studies found that using probiotics did not affect the risk of premature birth before weeks 34 and 37 of pregnancy.

However, other researchers found that drinking milk with probiotics in early pregnancy reduced the risk of premature birth. Doing so later in pregnancy reduced the risk of preeclampsia.

With probiotics in the gut, experts say that greater variety suggests better health. For the vagina, the opposite applies, and experts say that clear dominance of Lactobacillus bacteria is a sign of vaginal health.

Researchers note that one particular strain called L. gasseri has a notable ability to stick to the walls of the vagina, which can make it particularly helpful in restoring the balance of microorganisms in this part of the body.

Scientists have also identified L. iners and L. rhamnosus as helpful microorganisms.

Studies have found that an oral dose of more than 1 billion live organisms could result in a vaginal microbiome with a dominance of Lactobacillus.

One group of researchers found that although capsules for vaginal insertion were effective for some people, oral pills seemed to be the best choice.

Manufacturers typically sell probiotics as dietary supplements, which are subject to less strict regulations than medicines. Therefore, it can be difficult for consumers to know how effective these “live” cultures are and how strong a dose they are taking.

The vaginal microbiome is a complex environment comprising different kinds of microorganisms. Researchers have identified more than 250 species of bacteria that live in the vagina.

The most important and prolific bacteria living in the vagina are Lactobacillus. There are many different species of this bacteria, and the most common ones are:

  • L. crispatus
  • L. iners
  • L. gasseri
  • L. jensenii

Most commercially available probiotics contain two different species: L. rhamnosus and L. acidophilus.

Other bacteria present in the vagina include:

  • Atopobium
  • Corynebacterium
  • Anaerococcus
  • Peptoniphilus
  • Prevotella
  • Gardnerella
  • Sneathia
  • Eggerthella
  • Mobiluncus
  • Finegoldia

Probiotics are living organisms that many people claim to offer a variety of health benefits.

Interest in using probiotics for vaginal health is growing, but there are still not enough comprehensive or conclusive studies to determine whether taking probiotics is effective.

Probiotics may be helpful in treating BV and yeast infections, especially when a person uses them in combination with traditional antibiotic therapy.

Anyone interested in taking probiotics for vaginal health should speak to a doctor or pharmacist first.