Keto Crotch headlines have ricocheted around the Internet.

Whether this is just a click bait sweet spot of vaginal panic + keto or something more orchestrated (the number of headlines that blossomed in such a short span was truly awe-inspiring) is hard to know. I am not a conspiracy theorist, but seriously it was nuts even by vaginal mayhem standards. Not even the power of winter vagina could do that!

Before we dive further into Keto Crotch — words I never dreamed I would write — let’s be clear about one thing. The plethora of articles about supposed vaginal odors from food are misogyny (blatant or internalized), represent zero understanding of vaginal physiology, or both. If there were equal number of think pieces devoted to scrotum stank and anus aroma, I’d accept the Internet likes to obsess over intimate places and that false genital panics are an equal opportunity offense.

However, the lack of articles about the way a penis, scrotum, or rectum might smell depending on diet, weather, or underwear/jockstrap leads to only two possible conclusions: everyone thinks smegma has floral and pine notes and behind the scrotum is a pleasing mix of anise and musk OR these articles exist because it is only vaginal panic sells copy.

Back to keto crotch.

The claim: excess ketones from nutritional ketosis enter the vagina and change the smell.

Ketones 101

When the body doesn’t have enough sugar for energy (sourced from carbohydrates) or can’t use the sugar it has (in the case of diabetes) the liver breaks down fat for energy. Ketone bodies or ketones are by products of this process. The three ketones that are produced are acetoacetate, acetone, and beta-hydroxybutyrate.

Normally, the concentration of ketones in the blood is less 1 mg/dl.

Ketones are used as energy and any excess are removed. The main elimination route is the lungs. Acetone in exhaled breath produces a fruity, nail polish smell that should be familiar to every doctor. Excess ketones are also removed by the kidneys in the urine.

If ketones are produced to such a degree that the body can’t remove them fast enough, ketoacidosis develops meaning the pH of the blood drops (among other things) and this is a medical emergency. Ketoacidosis is not seen with nutritional ketosis, which is the goal of the keto diet.

What about sweat as a source of ketone removal? I can no find no convincing evidence that ketones are removed via sweat glands or that ketones increase in sweat with nutritional ketosis. It is quite possible people who think their body odor changes with nutritional ketosis are simply smelling their own keto breath.

If some new technology eventually tells us that ketones are in sweat, it will be something that happens to both men and women. Sweat and secretions from apocrine sweat glands (specialized glands in the groin) can contribute to genital odor for both men and women. This is why your underwear may smell a musky after wearing them all day after a heavy work out, but the odor is from the skin not vagina. I shouldn’t have to point out the unique smell of a well-used yet infrequently laundered jock strap, so no vagina required at all for underwear aroma.

Keto rash, a real thing, is not from ketones in sweat, it is a condition called prurigo pigmentosa and is likely due to negative effects from ketosis on the immune system. That a diet induces a rash in this (or any manner, really) is not a selling point for me. But I digress.

How does the vagina fit into this? Ha ha. It doesn’t.

The vagina is not a filter for waste products. The lungs and kidneys are, which is why THEY dump ketones.

Most of what makes up vaginal discharge and odor is an inside job — vaginal bacteria and the substances they produce, potentially harmful bacteria packaged for elimination on epithelial (skin) cells, epithelial cells, and cervical mucous. Only very tiny amount of what makes up vaginal secretions comes from the blood stream. Like the smallest, tiniest part of the 1-3 ml a day of vaginal discharge. This is called transudate and it is a ultrafiltrate, meaning it has few if any cells and no proteins. Transudate is fluid that has leaked from blood vessels close to the vagina, travelled through the smooth muscle of the vagina and between the cells of the vagina, and then into the vagina.

The idea that ketones can even make it into the vagina is not proven and to me seems suspect biologically. I can’t find any supporting data. The vagina uses sugar not ketones as an energy source (for lactobacilli, the good bacteria). So biologically, it seems the vagina would prefer to be ketone free.

I smell vaginas all day long (it is part fo the work up for vaginal conditions) and in the absence of two specific medical conditions (bacterial vaginosis and Trichomonas) there is a pretty uniform smell. I have many patients on the keto diet or who are paleo or vegetarian or vegan or, well, you get the point. I couldn’t tell you who is on what diet based on their vaginal exam.

Stop the Vaginal Panics

The false idea that food, especially punget food, can change vaginal smell is promoted by many magazines, “influencers,” and even doctors, who are all clearly woefully misinformed.

The myth is so pervasive that I have a whole chapter in my book, The Vagina Bible, walking people through the medical misinformation step-by-step. Seriously, if your GYN thinks food can change the way your vagina smells my advice is get a different doctor.

If ketones are in sweat (not proven) this would affect the smell of the “crotch” for women and men equally.

If you are on the keto diet and you think your vagina has a different smell, consult a doctor not the Internet. If your work-up is negative, it is entirely possible you are smelling your breath as nutritional ketosis can give you bad breath.

And why the Internet isn’t in a panic about Keto Breath and how it affects kissing, but is obsessed over non-existent Keto Crotch pretty much says it all.

Shaming women about vaginal health is profitable.