Keto Crotch: The Secret Keto Diet Side Effect?

The ketogenic diet, popularly referred to as the keto diet, is a high-fat, low-carb diet designed originally to help children with epilepsy and now safely used by adults to shed body fat and improve blood sugar levels. When you deny your body the quick-use energy of the sugar in carbs (glucose), you force it to break down fat for energy (ketone bodies). The only problem? In the first few days of transitioning into a state of ketosis, people often experience keto flu symptoms like brain fog, keto diarrhea or cramps, and keto breath. What people tend to talk about less, however, is keto crotch. It’s important to discuss so that you can tell the difference between normal symptoms and gynecological concerns. Let’s demystify this topic once and for all.

The Smell of Ketones

By getting at least 75% of your calories from fat and 5% or less of your calories from carbs, you manipulate your body into ketosis, a metabolic state that rapidly and safely burns fat and helps you lose weight. The long-term side effects of maintaining this state are incredibly beneficial: lowered risk of cardiovascular disease, lowered risk of type 2 diabetes, more energy, and a healthier body composition. Unfortunately in the early days of reaching ketosis, there are some unpleasant side effects that you have to get through first.

One of the best ways to know whether you’re in or approaching ketosis is to test for ketone bodies in your breath, blood, or urine. Some keto dieters notice that they have bad breath as they transition into ketosis, a fruity, metallic acetone smell (not unlike rotting fruit alcohol or nail polish remover) that they desperately try to cover up with sugar-free gum or mints. However, some also notice the smell of their urine change, and with it a new and concerning vaginal odor—this is likely the smell referred to as “keto crotch.”

Think about it: if you have a lot of coffee or apple juice in one day, you can often smell it in your crotch area and urine later.  Vaginal pH has a very delicate balance and, not unlike the mouth, the vagina and all its inner membranes are directly impacted by what we consume. If you’re consuming more fats than carbs, your whole body is full of ketone bodies. In the early days of keto you produce more than you can use as the body adapts to its new fuel source, and those ketones are being breathed out, peed out, and excreted in any way possible.

The Vaginal Smell Test

Keto crotch wouldn’t be so worrying if vaginal smell wasn’t such an important diagnostic aid. Doctors and gynecologists urge women that if their crotch area has a new, foul smell or discharge to consult with a health care professional immediately, because it could be the sign of an infection in the vagina or even elsewhere: a urinary tract infection could be detected by smell before it becomes a life-threatening kidney infection.

Any strong, irregular odor may be a concern. For example:

• A fishy odor: This could be the sign of bacterial overgrowth in the vagina, known as bacterial vaginosis.
• A bread-like odor: Whether sweet or sour (cookie-like, beer-like, flour-like), a bready smell is the sign of a yeast infection.
• Other vaginal odors: Certain STIs (sexually transmitted infections) can cause a change in odor, as can poor vaginal hygiene, or ill-fitting fabrics or clothing that traps sweat.

Douches meant to clean the vagina are not recommended as they can upset vaginal pH levels (especially the scented ones). 

But how worried should you be if you suspect this new odor is due to ketones? One study from the Journal of Nutrition in 2007 said there was an association between high-fat diets and more severe cases of bacterial vaginosis. Could your weight-loss program be disturbing the health of your vagina?

What We Know About Keto Crotch

If one potential side effect of the keto diet is keto crotch, what’s the procedure? Do you wait it out, or go to the doctor right away? Any unusual smell down there lasting longer than a day or two usually merits a doctor’s visit, but if it’s just a whiff of ketones, should you be worried?

Long story short: if you’re worried, ask a doctor.

While it is possible for your crotch area to smell strange due to the new ketone chemicals in your system (acetoacetate, beta-hydroxybutyrate, and acetone), some people swear that keto crotch isn’t a real thing at all, and unfortunately there is no science confirming or disavowing this particular aspect of the ketogenic diet.

That means the information out there on keto crotch is anecdotal—some people detect a pervasive acetone smell in their breath, urine, and even poop, and some people don’t. Without scientific study in this area, there are too many variables at play: maybe some people have smelly crotches but their senses of smell aren’t sensitive enough to detect it…or maybe some people are destined to get all the symptoms of keto flu while other people hardly get any? Without clinical study, we just can’t know for sure.

Should I Ask My Doctor About Keto Crotch?

Even if keto crotch is real and stinking up your underpants right now, if you’re at all concerned, please consult a women’s health professional. Why?

• Changing your diet may change your vaginal pH, making you more susceptible to opportunistic infections.
• Keto crotch odor could be masking another odor that indicates a serious vaginal infection.
• You may be interpreting this odor as keto related if you’ve just begun keto, but it could be coincidental. 

The same goes for an unexplained odor as it does for so-called keto rash: ob/gyns recommend that you never dismiss vaginal red flags like abnormal discharge, odor, or rash. For all you know these aren’t keto flu side effects but a previously undiscovered allergy to new foods or supplements in your diet. Only a doctor can tell you for sure.

Keto Crotch Concerns

If your breath smells or your stomach is churning because you’re not used to eating high levels of fat, or you have a keto headache, you may not be too concerned, as these are expected side effects of the early days of entering ketosis. They are temporary, and there are supplements you can take to help your body reach ketosis faster. However, there are no sure answers about so-called keto crotch outside of trending topics on social media and reddit forums, and when it comes to vaginal health, it’s not worth the risk to wait it out.

If a keto crotch smell persists, if it comes with any other symptoms like rash, burning, itch, or abnormal discharge, it’s time to consult a doctor. Don’t douche, as that can further disturb the area, and ask a professional as soon as possible to rule out any underlying problem.