• 07.31.13

Condoms Don’t Just Protect Against Bad Bugs, They Help Good Ones

Scientists have found that using protection does a lot of good for the vagina’s microbiome. So wrap it up: chivalry now comes in latex.

There’s a really disturbing scene at the end of Tim Burton’s The Nightmare Before Christmas, in which the villain, a character by the name of the “Oogie Boogie Man,” unravels. Not psychologically. Oogie Boogie, as it turns out, is just a potato sack shaped somewhat like a starfish, and is filled with all sorts of creepy, crawly bugs that work together to allow Oogie Boogie to walk and talk and scare other characters. When a loose string gets pulled at the end of the film (sorry, spoiler), all those bugs come tumbling out.


The human body is also full of bugs, and some 100 trillion at that. Scientists call that ecosystem the “human microbiome,” and it’s basically made up of all the bacteria in our bodies that work together (or in opposition) to allow us to function. Scientists are just beginning to map out the gut microbiome, for example, which can possibly impact everything from obesity to mental illness. And it turns out that, at least for women, condoms are a big help for microbiome wellness.

That’s because the vagina has its own microbiome, too, and much of it still remains a mystery–though it’s critical to our overall health. Take it from Moises Velasquez-Manoff, a microbiome-focused journalist who wrote an explainer about the “vaginal community” of bacteria earlier this year:

“A healthy vaginal microbiome produces lactic acid and hydrogen peroxide, which maintain a level of acidity that keeps troublemaking microbes at bay. When the vaginal community becomes unbalanced, on the other hand, acidity decreases. The wrong microbes may then invade or, if they’re already present, bloom.”

When good bacteria die off and bad bacteria succeed, it leads to a nastily unbalanced ecosystem. Vaginosis is a term for a vaginal microbiome that’s losing the war, and it affects nearly 30% of American women, though many don’t even know they have it. Still, vaginosis has serious implications–it can lead to preterm birth and increases risk of acquiring herpes or HIV.

Chinese researchers, however, may have discovered something that makes our vaginal microbiomes healthy and pleasant places to be. In a paper published in PLoS One, the researchers find that condoms, of all things, actually increase the presence of a type of bacteria called lactobacillus–the good guys in the ongoing battle for microbiome dominance.

The researchers at Beijing Friendship Hospital collected swabs from 164 married women who didn’t use the pill and measured them for the presence of lactobacilli. They found that the women who used condoms consistently had a significantly higher lactobacilli count than women who used an IUD or the rhythm method.

“The prevalence rates of women colonized by cultivable Lactobacillus in the condom, IUD and rhythm groups were 95.8%, 84.2% and 88.6%, respectively,” the study notes. “As a perfect barrier, condom can help maintain the vaginal acidic buffer system and the vaginal lactobacilli population when sperm (pH 7.0 to 8.0) enters vagina during sex.”

Hear that? Condoms not only prevent pregnancy, but are integral to our vaginal acidic buffer systems (which, according to, function the best at the acidity level of tomato juice or beer). So chuck that pineapple juice, and…good luck out there.

About the author

Sydney Brownstone is a Seattle-based former staff writer at Co.Exist. She lives in a Brooklyn apartment with windows that don’t quite open, and covers environment, health, and data.