Wellness culture is coming for your vagina. On Instagram, in the vitamin aisle, and even on the subway, the billion-dollar “feminine probiotic” industry promises healthier, better-smelling, infection-free genitalia.

The proliferation of vaginal probiotic supplements and suppository capsules is driven, in part, by frustration: there are few effective treatments for conditions related to the vaginal microbiome.

“There’s a real hunger for more science and more options,” says Smita Gopinath, an assistant professor of immunology and infectious diseases at the Harvard TH Chan School of Public Health who researches vaginal bacteria. Treatments for vaginal microbiome-related conditions, such as urinary tract infections and bacterial vaginosis, have remained the same for decades, she explains. “It’s incredibly frustrating.”

But the science behind the vaginal microbiome is far from settled. Researchers still lack basic answers about how it works – and early evidence suggests that improving it may be more complex than popping a pill.

What is the vaginal microbiome?

The vaginal microbiome is a complex ecosystem of viruses, bacteria and fungi inside the vagina.

It is an “unusual community,” says Gopinath. Unlike the gut, where a diverse array of bacterial species is ideal, a simpler vaginal ecosystem dominated by a single species is associated with better health.

We are learning more about these microorganisms, due to advances in molecular sequencing, says Dr Caroline Mitchell, a physician-scientist and director of the vulvovaginal disorders program at Massachusetts general hospital.

“The next frontier is not just knowing [what’s] there, but what they are doing,” says Mitchell.

What makes for a healthy vaginal microbiome?

Generally, the hallmark of a healthy vaginal microbiome is an abundance of Lactobacillus, a bacterial species. Lactobacillus-depleted microbiomes are linked to adverse health outcomes, like bacterial vaginosis, preterm birth, and an increased risk of sexually transmitted infections.

Researchers are working to understand how these bacteria optimize vaginal health, Mitchell says, but they still don’t know for sure; it’s also possible for healthy individuals to not have these bacteria. Early evidence suggests that different strains may perform useful roles, such as reducing inflammation.

Understanding why and how these bacteria promote good health could lead to therapeutics that mimic their effects.

One thing we do know is that lactobacilli dominance results in a slightly acidic vaginal pH. Many products claim to alter pH levels so as to achieve “balance”, but “what we’re really looking for is not balance”, Mitchell says. The bacteria produce lactic acid, and this lower pH level helps prevent an overgrowth of harmful bacteria.

In addition, “you cannot durably change the pH by using a low pH product in the vagina,” says Mitchell. “That’s been tried, and it doesn’t fix the bacterial community.”

Unlike the gut microbiome, which responds to diet, the vaginal microbiome is hormonally acquired. During puberty, bacteria such as lactobacilli take over the lining of the vaginal canal. Researchers don’t know how and why this happens.

How do I take care of my vaginal microbiome?

Typically, the vaginal microbiome doesn’t require intervention, explains Mitchell. If you feel normal, it’s likely healthy. The vagina is self-cleaning; you don’t need to wash it.

The vaginal microbiome can experience issues, but products often claim to fix problems without much supporting evidence, says Sharon Hillier, a microbiologist and a professor of obstetrics, gynaecology, and reproductive science at the University of Pittsburgh.

For unusual sensations in the area, such as itching or irritation, ask a care provider for a vaginal culture test before starting any treatments, says Dr Gloria Bachmann, a physician and professor of obstetrics, gynaecology and reproductive sciences at the Rutgers Global Health Institute.

That way, “you’re not blindly taking an intervention that may not work [or] may sensitize your good bacteria, your good fungi, and your good viruses,” says Bachmann.

Some factors negatively affect the vaginal microbiome, says Hillier. Antibiotics can disrupt it by killing beneficial bacterial species. Unprotected sex may disrupt the vaginal microbiome because it can introduce foreign bacteria and semen. Douching and spermicides can cause an imbalance, while combined oral contraceptives seem to support a stable microbiome. Using menstrual cups is associated with a greater likelihood of a healthy vaginal microbiome than pads or tampons.

Why are there so few treatment options for the vaginal microbiome?

“There’s not been a lot of progress for patients in this field,” Gopinath says.

People with vaginal health issues live day to day in discomfort and pain, Gopinath says; these infections are also medical “risk multipliers”. For example, bacterial vaginosis is a risk factor for sexually transmitted infections, likely because it reduces natural defenses against infection.

A lack of answers and attention from medical professionals fuels patient frustration and interest in probiotics, says Mitchell.

Limited education and understanding of vaginal health can also make it difficult for some to tell the difference between normal vaginal symptoms and a medical issue, says Hillier.

For instance, a partner’s comments about vaginal taste or smell may cause worry, even if there is no problem. As a result, some may seek out products to fix a problem that doesn’t actually exist, Hillier explains.

Do vaginal probiotics work?

Currently, no products can reliably and comprehensively shift the vaginal microbiome to a Lactobacillus-dominant state, Mitchell says. She also notes that the regulatory pathway for new drugs is “moderately challenging”: there is no formal FDA classification for an at-risk vaginal microbiome. Additionally, with the high cost of bringing new medications to market and a historical lack of investment in women’s health, there has been limited progress.

Recurrent bacterial vaginosis (BV) is the clearest case for when microbiome intervention is most helpful, says Mitchell. Researchers don’t know the direct cause of BV, but the condition is associated with an excess of harmful bacteria.

No probiotic treatments have definitively proven effective, but ongoing research suggests that one is possible. Mitchell co-authored a 2026 paper showing that, in a phase 1 randomized clinical trial, a short course of a vaginally delivered multi-strain probiotic restored protective bacteria to the vagina. These effects lasted up to 12 weeks. There are plans for a follow-up trial, with the eventual goal of getting FDA approval for a biotherapeutic for BV.

However, current evidence is insufficient to conclude that interventions involving Lactobacillus strains can prevent or treat these conditions, Mitchell notes.

“I hope more consumer demand for vaginal health products will drive the industry in a good way,” says Mitchell.

Commercial interest in vaginal microbiome products already influences clinical practice, though it’s likely premature. Preliminary research by Hillier suggests that a small percentage of women are advised by their care providers to use probiotics for conditions related to the vaginal microbiome, such as urinary tract infections, despite a lack of high-quality evidence supporting this recommendation.

Most of the claims about these products lack scientific evidence to support them, says Hillier. Under US law, manufacturers cannot claim supplements treat diseases, but they can suggest that the product will convey health benefits without proof.

The FDA doesn’t require supplements to undergo safety testing before marketing, and it doesn’t verify a product’s ingredients. This lack of regulation means it’s impossible to know what’s in them, says Hillier.

Even if a supplement contains helpful bacteria, that can be misleading because it may not actually be helpful. This can “make it look like it’s a real scientific product, but it’s not”, Hillier says.

It’s unlikely that orally consumed strains can influence the vaginal microbiome, says Gopinath. They would have to survive the gastrointestinal tract to do so. Products designed for vaginal application, such as suppositories, could be more successful, but more data is needed.

Beyond the disappointment and cost if they prove ineffective, some probiotics may cause gastrointestinal side effects, says Mitchell.

Don’t self-diagnose without proper testing. If you assume you have a condition like bacterial vaginosis but actually have something else, such as chlamydia, you could delay getting the appropriate treatment and care.

As consumers look for ways to support the vaginal microbiome, researchers are also ramping up efforts to better understand it, says Gopinath.

“I’m very optimistic scientifically about the future for this,” says Gopinath.