It’s no secret the keto diet comes with some icky side effects. Keto flu, keto breath, keto diarrhea—yep, this weight-loss plan has a dark side. But some women say that they’re experiencing one especially nasty keto diet byproduct: keto crotch, or a stinky vagina.

“I’ve been on the diet for about a month and a half now and I’ve noticed that my vaginal odors have gotten MUCH stronger,” user SxarAnise wrote on Reddit. “I’m not exactly sure how vaginas are ‘supposed’ to smell like. Many say ‘musky’ but I feel like that’s too mild of a word… It’s much stronger than ‘musk’ for me.”

Other users chimed in to say they’ve experienced the same thing. “Oh boy, yes. During the first few months there was some extra smell stuff happening all over—crotch and otherwise. But the good news is that it settles down and goes away after you’ve been keto for awhile,” one wrote.

“It is horrible,” another wrote. “I have to keep panty liners (hate that name!) in my bag and keep changing them every couple of hours. It’s a pain.”

“I’m glad this was posted because I just changed my underwear AGAIN today because I smelled gross,” complained yet another commenter. “At least I know I’m in ketosis, I guess…”

We’re not doubting these keto followers; if they say their lady parts are stinkier since they’ve gone keto, we’ll take them at their word. But it does beg the question: Scientifically speaking, why would a diet that’s high in fat and very low in carbs change the scent of your vagina?

Of course, this isn’t the first time we’ve heard claims that what you eat affects your down-below scent. Remember when Kim Kardashian shared an image of herself cracking open a can of pineapple juice with one leg up, implying in her caption that this tropical beverage could make your vagina smell and taste better? Sorry Kim, but no research backs this claim.

On the other hand, science does show that going keto can change the odor of your breath and urine, making them smell like nail polish remover.

That’s because when your body breaks down fat for energy instead of carbs (which is the goal of keto), it converts the fatty acids into chemicals called ketones. It then disposes of the ketones through both exhalation and urination. “One type of ketone, acetone, is an ingredient in some nail polish removers, which is why your breath may smell like this familiar scent,” Cynthia Sass, RD, Health contributing nutrition editor, said previously.

The release of ketones might also result in keto crotch, but it’s never been researched. And it’s not like smelly pee is going to stink up your vagina. “Your urine isn’t going to make your vagina smell,” Dr. Streicher confirms.

Some experts have theorized that the keto diet changes vaginal pH (the balance of bacteria in your vagina), which in turn can alter your vaginal scent. It’s true that if your vaginal pH is thrown off, you’re at a higher risk for developing bacterial vaginosis (an overgrowth of bacteria in the vagina), which can have a funky odor, Dr. Streicher says. But unfortunately, no research exists showing that diet alone can alter vaginal pH.

So while plenty of women are sure the keto diet is the cause of their odorous vagina, no science yet supports this. If you follow keto and start noticing that your lady parts are smelling rank, consider checking in with your ob-gyn. “It’s never normal for your vagina to have an odor,” Dr. Streicher says.

Is it real?

Some people notice that they have increased vaginal odor and discharge on the keto diet.

Keto crotch has not been the subject of scientific investigation yet. However, it is possible that keto crotch could be bacterial vaginosis (BV).

Bacteria known as lactobacilli are important in ensuring the acidic environment of the vagina, which helps to maintain the natural vaginal microbiome. BV occurs when the environment in the vagina changes, and other bacteria replace the lactobacilli.

The potential hydrogen (pH) scale measures how acidic or alkaline something is. The typical vaginal pH during reproductive years is around 4.5 pH.

According to an older 2007 study, a diet high in fat may cause a high vaginal pH. The study found that the participants who had a diet high in fat also had an average vaginal pH of 5.1. A vaginal pH of more than 4.5 may be an indicator of BV.

The study suggests that a diet high in fat may increase the risk of bacterial infections related to BV by increasing the risk of other bacterial growth.

A 2020 review reinforced the links between a diet high in fat and the occurrence of BV. However, it also noted that saturated fats may be a significant link.

As the keto diet consists of consuming large amounts of fats and small amounts of carbohydrates, there may be a link between the diet and BV.

A diet high in fats may change the vaginal pH, leading to an environment in which BV can occur.