BV gets treated like it’s only her problem. It isn’t. A 2025 study in the New England Journal of Medicine found that treating the male partner too cuts repeat infections almost in half. That’s a big deal, and most people have never heard about it.
Here’s the basic fact first. Men don’t get BV. They don’t have a vagina, so there’s no vaginal microbiome to throw off balance. The condition just doesn’t apply to male bodies.
But men carry the bacteria anyway. Right there on the skin. Inside the urethra too. No itching, no smell, no sign at all. He walks around completely unaware.
And it moves during sex.
Think about how many couples deal with this exact loop. She takes antibiotics, feels better, maybe even forgets about it for a month. Then the discharge is back. The smell’s back. She’s sitting in another waiting room, thinking something’s wrong with her body specifically. Nothing is. Her partner just never got treated.
So here’s what the research actually says, what shows up (or doesn’t) in men, and what to do about it.
Key Takeaways
- Men don’t get BV. They do carry Gardnerella vaginalis.
- Sex moves the bacteria between partners.
- Treating the male partner lowers her recurrence rate.
- The 2025 NEJM trial: 63 percent recurrence without partner treatment, 35 percent with it.
What Is Bacterial Vaginosis?
Bacterial Vaginosis is the most common vaginal infection in women aged 15 to 44. What happens is simple enough. Lactobacillus, the bacteria that normally keeps things balanced, drops off. Gardnerella and a few other species (Prevotella, Atopobium vaginae) move in and take over.
Symptoms, when they show up:
- Thin discharge, gray or white
- Fishy smell, worse after sex
- Itching
- Burning during urination
A lot of women get none of this. Zero symptoms, infection still there. That’s part of why BV confuses people. It’s not one bug invading you. It’s a shift in which bacteria are winning.
Can Men Get Bacterial Vaginosis?
No. Flat out. BV is defined by vaginal microbiome disruption. Men don’t have a vaginal microbiome. End of story, biologically speaking.
Here’s the part that actually matters, though. The penis has its own bacteria living on it, and Gardnerella vaginalis shows up there often. Men carrying it feel totally normal. No symptoms. He genuinely has no idea.
The 2025 NEJM trial followed 164 heterosexual couples for 12 weeks.
One group: women got antibiotics, partners got nothing.
Other group: women got antibiotics, partners got oral metronidazole plus a clindamycin cream applied topically.
Recurrence rates after 12 weeks? 63 percent versus 35 percent.
That’s almost double, just from leaving him untreated. He’s fine. She’s not. And the bacteria keep bouncing back and forth.
Can BV-Related Bacteria Live in the Penile Microbiome?
Yes. This isn’t a one-off finding either; it shows up across multiple studies.
Back in 2015, researchers identified seven distinct bacterial community types found on the penis (vaginal bacteria get sorted into five types, for comparison). Men whose bacteria fell into certain categories carried more BV-linked species, and their partners were more likely to have BV.
Then in 2016, a study compared actual couples. Penile skin bacteria and vaginal bacteria from the same pair looked alike. Strikingly alike, in fact, when the woman had active BV.
None of this makes the guy sick. No symptoms at all. Which is exactly the problem.
Doctors used to assume men weren’t involved because, well, nothing showed up in exams. Turns out that logic was backwards. No symptoms doesn’t mean no bacteria. He can feel completely fine and still be the reason she keeps relapsing.
Do Penises Have a Microbiome?
Yes, and there are two spots researchers look at.
One is the coronal sulcus, basically the groove where the head meets the shaft. Bacteria here stay fairly stable over time. Circumcision changes what lives there too; circumcised and uncircumcised men end up with different bacterial makeups, partly because foreskin holds in moisture.
The other spot is the urethra. This one shifts around more, less predictable from sample to sample. Usually tested through urine or a direct swab.
These two zones don’t match each other, and neither matches vaginal bacteria exactly, though sex blurs the lines fast once a couple’s been together a while.
Why does this matter? Because for decades BV got treated as strictly a female condition since men showed nothing visibly wrong. Now we know male anatomy is hosting its own active bacterial community, one that trades information with a partner’s vaginal microbiome every time they have sex.
Is Bacterial Vaginosis an STI?
Technically, no. Health agencies don’t list it as one. Women who’ve never had sex still get BV, so sex can’t be a requirement.
That said, BV behaves like one in a lot of ways. Symptoms tend to show up roughly four days after sex. New partner? Higher risk. Same partner repeatedly? Higher odds it keeps coming back.
Even doctors admit they don’t fully know why. University of Rochester physicians point to two competing theories. Maybe partners pass specific bacterial strains directly to each other. Or maybe sex itself just disrupts the vaginal environment enough that Gardnerella takes advantage, regardless of what bacteria anyone brought along.
The CDC updated its position to acknowledge sex as a contributing factor. That’s new, relatively speaking. And the 2025 NEJM data adds more weight behind it, treating the male partner cuts recurrence nearly in half.
One more thing worth saying. This isn’t only a heterosexual issue. Women who sleep with women pass vaginal bacteria back and forth too.
Do Men Spread BV?
They don’t catch it. They spread what causes it. Different thing entirely, and the distinction matters for how doctors should treat this.
A 2015 study followed 165 uncircumcised men. The ones with more than one female partner besides a spouse carried higher levels of BV-linked bacteria. Their spouses faced higher BV risk after sex without protection.
A 2013 study, 157 heterosexual men this time, found something similar. Men with a history of nongonococcal urethritis (often linked to chlamydia or mycoplasma) carried more BV-associated bacteria on the penis than men without that history.
Add it up, and the picture’s pretty clear. Male partners carry the bacteria. Unprotected sex moves it. Recurrence climbs. Condoms during treatment cut that transfer down noticeably, which gives couples something practical to do right now while formal treatment protocols catch up.
BV Symptoms in Men
Basically none. That’s the whole answer.
Which creates a strange gap for couples dealing with repeat BV. He feels fine. She keeps cycling through treatment. Nobody connects the two because there’s nothing pointing at him.
A handful of men report mild irritation or light discharge sometimes. Usually that traces back to a totally different infection running alongside the BV bacteria, not the bacteria itself. BV only affects vaginal tissue by definition, so whatever he’s feeling has its own cause.
If your partner has actual symptoms, get him checked. Don’t assume BV. It’s probably something else.
What Conditions in Men Cause Similar Symptoms?
A few conditions mimic BV closely enough to cause real confusion: discharge, itching, burning, odor. Worth ruling these out before blaming partner bacteria for anything.
Thrush (Male Yeast Infection)
Candida overgrows on the penis, often under the foreskin. Itching, redness, a white chunky buildup.
Tight clothing, heavy sweating, unprotected sex, all raise the odds. And yes, it passes back and forth between partners just like BV bacteria does.
Fungus causes this one, not bacteria. Antifungal cream clears most cases in one to two weeks. If it keeps coming back, get checked for diabetes; that’s sometimes the underlying driver.
Sexually Transmitted Infections
Chlamydia and gonorrhea both cause discharge and burning that look a lot like what a woman reports during a BV flare. Both spread through unprotected sex. Both frequently show zero symptoms in men.
That last part is why testing matters so much here. Untreated, these infections inflame a partner’s vaginal tissue too, which sometimes gets mislabeled as BV that just won’t go away. Testing both people sorts out what’s actually going on.
Condoms help with both problems at once, worth mentioning.
Urinary Tract Infection
Rarer in men, but it happens. Usually E. coli bacteria traveling into the bladder or urethra. Learn more about kidney infection symptoms and care if urinary symptoms persist or worsen.
Burning while peeing, cloudy or bloody urine, pelvic discomfort. Sounds a lot like a BV flare from the outside. A quick urine test clears up the confusion.
Antibiotics knock it out within days, typically. If it keeps recurring, something structural or prostate-related might be behind it.
Balanitis
Inflammation at the head of the penis, more common without circumcision. Over-washing, scented soap, untreated diabetes, or an underlying STI can all cause it.
Sometimes swelling makes the foreskin hard to retract. Add itching and discharge, and suddenly it looks exactly like something BV-related, even though it isn’t.
A doctor diagnoses it through an exam, sometimes a swab. Treatment depends entirely on what’s causing it.
Recurrent BV and Your Male Partner
Two rounds of antibiotics. Maybe three. And BV keeps coming back a few weeks later anyway. Your partner might be the reason, and it’s worth considering seriously. For ongoing or repeated symptoms, explore support for recurrent vaginal infections.
Research shows BV-associated bacteria survive on the penis for at least two months after vaginal sex. Without treating him, reinfection isn’t just possible; it’s likely.
The NEJM trial backs this up with real numbers. 35 percent recurrence when partners got treated. 63 percent when they didn’t. Nearly double. That’s one of the clearest findings in BV research in a long time.
So when should you actually bring up partner treatment? Two or more episodes in six months. Symptoms returning right after sex with the same person, every time. Finishing full antibiotic courses and relapsing anyway. Any of those, it’s worth a real conversation.
Most clinics haven’t caught up yet, to be fair. Practice still varies a ton depending on who you see. But the evidence keeps building, so raising it with your doctor is a reasonable thing to do.
Should Male Partners Seek BV Treatment?
The bacteria don’t hurt him at all. Zero health risk on his side. Treatment exists purely to stop transmission back to her.
Older studies tried oral antibiotics alone on male partners and found nothing, no benefit over placebo. That’s part of why doctors dismissed partner treatment for so long.
The 2025 study tried something different: oral metronidazole combined with a topical clindamycin cream right on the penis. Two groups: one untreated, one given the full seven-day combo.
Results: 35 percent recurrence versus 63 percent. The topical component looks like the key difference; it actually gets at skin bacteria in a way oral medication alone never did. Which probably explains why earlier trials failed.
Bottom line, if repeat BV is a pattern for you two, this study is worth bringing to your provider directly.
Treatment Options for BV in Men
No official guidelines exist yet, since men technically don’t get BV. But the research points toward specific options.
Oral metronidazole for seven days. Topical clindamycin cream applied directly. Or both together, the combination that performed best in the 2025 trial.
None of this treats an infection in him; there isn’t one. It’s purely about lowering bacterial load so he doesn’t reintroduce it to her later.
Some providers add probiotics into the mix for balance. The evidence there is thinner than the antibiotic data, worth knowing before you assume it’s equally proven.
Access is still spotty, though. A lot of clinics won’t treat a man without his own diagnosis, and there’s no diagnosis to give since BV doesn’t apply to him. Some platforms now offer direct male partner treatment, skipping that requirement entirely.
Prevention Tips for BV Transmission Between Partners
- Condoms, consistently. They block transfer and keep semen from shifting vaginal pH, which is one of the common triggers for overgrowth in the first place.
- Dental dams for oral sex; the same logic applies.
- Circumcision lowers BV-associated bacteria on penile skin according to several studies. That’s obviously a bigger decision than just BV prevention, so weigh it accordingly.
- Basic habits help too. Wash before and after sex. Skip scented products down there. Cotton underwear over tight synthetic fabric.
And remember, partner bacteria is one factor among several. Hormones, your cycle, whatever products you’re using- all of it shifts your microbiome independently. Prevention works best when you’re doing several things at once, not relying on one fix.
How to Talk to Your Partner About BV Treatment?
Nobody loves bringing this up. Vaginal health just isn’t something people talk about casually, even with a partner they trust.
Start with facts, not apologies. BV is extremely common. It has nothing to do with being unclean or unfaithful. Skip blame language entirely; frame it as something you’re dealing with together.
A 2020 study on how men perceive partner treatment found something useful here. Men who held less stigmatized views about STIs generally worried less about infidelity when their partner brought up a BV diagnosis. In the same study, these men actually saw agreeing to treatment as a way to show support, not as an accusation against them.
Keep it simple. Tell him about the 2025 numbers plainly: treating both of you together cuts her recurrence nearly in half. Frame it as a team thing.
Too many women carry shame around a diagnosis that’s not their fault. Bacteria don’t care who they’re in. Neither of you chose this.
How Do I Protect Myself?
- Condoms during vaginal and anal sex. Dental dams during oral sex.
- Fewer concurrent partners, generally speaking, lowers your risk. The research backs this up pretty consistently.
- Keep the area clean, including under the foreskin if that applies. Bacteria build up fast otherwise.
- Loose cotton underwear beats tight synthetic stuff. Heat and moisture feed bacterial overgrowth, simple as that.
These steps help with BV-related bacteria and a handful of other conditions carrying similar symptoms.
When to Seek Care?
Unusual discharge, persistent itching, burning when you pee, a fishy smell especially after sex- any of that means it’s time to see a provider.
For male partners, discharge, burning, redness, or swelling means get checked, though it’s probably something other than BV since BV doesn’t affect male anatomy.
And if BV keeps coming back within six months, bring up partner treatment directly. Mention the 2025 NEJM study by name if your provider seems unfamiliar; it’s recent enough that plenty of clinics haven’t caught up.
Frequently Asked Questions
Q1: What are male symptoms of BV?
Almost none. Occasionally mild irritation or light discharge shows up, but that usually points to a different infection entirely, not BV itself.
Q2: Can a girl give BV to a man?
Not BV exactly, since that’s limited to vaginal anatomy. She can pass him the bacteria, though, including Gardnerella vaginalis, and he carries it without symptoms until he passes it back later.
Q3: Why does my boyfriend keep giving me BV?
Semen shifts vaginal pH after sex, which creates conditions these bacteria like. He’s also carrying the bacteria on his skin without symptoms, so every encounter resets the cycle. Treating both of you together, per the 2025 trial, is what actually breaks it.
Q4: How do men get rid of BV-related bacteria?
Oral metronidazole plus a topical clindamycin cream, the exact combination tested in 2025. Cut recurrence in women from 63 percent to 35 percent. Probiotics sometimes get added, though that evidence is weaker.
Q5: Can men get tested for BV-related bacteria?
Yes, PCR testing picks up Gardnerella and related species from urethral or skin samples. Not routine yet at most clinics, but some specialists and telehealth platforms offer it now.
Dealing with Recurrent BV? Treat the Root Cause with Functional Medicine
Antibiotics clear BV temporarily, then the cycle restarts. Treating both partners together, now backed by real data from 2025, is a more complete fix than repeating the same prescription over and over. A functional medicine approach can help explore broader factors that may contribute to recurring symptoms.
Conscious Medicine looks at the whole picture- partner involvement, vaginal microbiome balance, lifestyle factors- instead of just another round of antibiotics.
Visit Conscious Medicine to see how a partner-inclusive approach helps couples actually break the cycle.
