Using a vaginal suppository majorly shortens that pathway, hence why much of the recent research on the vaginal microbiome has coalesced around these kinds of products. And yet, a couple studies suggest that even inserting Lactobacillus this way doesn’t always help these good bugs colonize the vagina or improve BV outcomes. The reason why may have to do with things like the viability of the bugs (a.k.a. whether they’re actually still alive in the product) and the particular species of Lactobacillus used, among other factors. As Dr. Mitchell points out, plenty of vaginal probiotics on the market feature kinds of lactobacilli that are commonly found in your gut but aren’t so predominant in the vagina, like L. rhamnosus, L. reuteri, and L. acidophilus—so it’s unlikely that inserting these microbes into your vagina would do much.
There may be an FDA-approved vaginal probiotic in the future—but until then, experts can’t wholeheartedly recommend you try these.
It makes a lot of sense, in theory, that a suppository packed with the right probiotics, alive and well, could nudge the vaginal microbiome toward health. The best evidence for that, Dr. Mitchell says, is a not-yet-available product called Lactin-V, which includes the primary vagina-centric species of Lactobacillus (L. crispatus) and is currently going through the FDA process to become a prescription drug. Research has shown it significantly reduces BV recurrence—just 30% of people who took a twice-weekly dose of the stuff for 10 weeks after receiving BV treatment wound up getting a repeat infection, compared to 45% of the placebo group. The study also found that the supportive bugs stuck around in people: The specific strain used was detectable in about 80% of participants for the length of the trial.
Still, further research found that only 48% of them maintained that new community of healthy bugs three months later—meaning, the benefits probably waned with time, too. Researchers are currently investigating how they can make that colonization last longer; Dr. Mitchell just wrapped a trial of a probiotic that includes multiple strains of L. crispatus, for example, with the idea that distinct strains might latch on better in different people.
As Dr. Gopinath points out, there’s no ideal vaginal probiotic just yet because there’s still plenty we don’t know about the vaginal microbiome, like how we even acquire it during puberty and what lets it stick around through disruptions like menstruation. It’s a tough thing to study because humans are, oddly, the only mammal with a Lactobacillus-dominant vaginal microbial pattern. Mouse models are often used to study the gut microbiome, but there’s no good equivalent for the vaginal one, Dr. Mitchell says. And of course, there’s the persistent problem of getting funding for research on anything involving the vagina, she adds.
So, for now, experts recommend a healthy dose of skepticism when it comes to the available products, which, reminder, haven’t gone through the rigorous testing required for medications. Much like with other supplements, there’s also no guarantee that you’re getting what’s promised on the label and in the stated dose(s), and that any probiotic strains included are even viable, Dr. Gopinath notes. (Nor can you be sure the product is free from random contaminants.) Because vaginal suppositories aren’t technically dietary supplements—you don’t take them by mouth—the regulatory clearance for these is fuzzy, and some are actually marketed as cosmetics, Dr. Mitchell points out, under the pretext of things like “odor control” (which, again, is more sexism than anything else). The bottom line is, it’s hard to know whether these products are safe to put into your body, via any hole, and if doing so will have any positive effect.
