Sex and Your Gut

By: Nicole Cain, ND, MA

Human sexual behavior¹ is regulated by key areas of the brain through the action of various hormones and neurotransmitters. Sexual excitation is driven by norepinephrine, dopamine, melanocortin, oxytocin, and vasopressin, while sexual inhibition is regulated by serotonin, opioids, prolactin, and the endogenous cannabinoid system.

Sexual Dysconnection

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What happens if you are dissatisfied with your, or your partner’s, sexual behavior? Sexual problems are common in both men and women and can occur at any age. According to a 2022 report,² approximately 40 percent of U.S. females report sexual concerns, while The Journal of Sexual Research³ reveals that 38.2 percent of surveyed sexually active men and 23 percent of women reported one or more of four specific sexual problems including lack of interest, difficulty achieving erection and/or climax, and discomfort with sexual activity.

Today’s conventional medical model typically emphasizes pharmaceutical therapies targeting neurotransmitter levels to address hypoactive sexual desire,¹ low libido, erectile dysfunction, low sex-drive, orgasmic disorders, and other symptoms. However, research suggests that there is an important factor that is often overlooked—the gut’s microbiome, which plays an important role in sexual health.

The digestive tract⁴ is a complex system composed of the mouth, esophagus, stomach, small intestine, large intestine, anus, liver, pancreas, gallbladder and microbiome. The microbiome⁵ is defined as the “commensal microbes, bacterial genetic material, functional microbial activities, and the ever-changing ecosystems of other cells, viruses, and bacteria” that has co-evolved with humans and is an integral component of overall health and wellness."

It is well established that an imbalanced gut microbiome is associated with myriad symptoms related to hormones, neurotransmitters, and immune health. Of particular relevance, recent evidence also suggests that gut bacteria may serve as a potent therapeutic target for addressing sexual dysfunction. This relationship is often referred to as the gut-sex connection.⁶

What is the gut-sex connection?

Sex and Gender

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The gut-sex connection consists of the relationship between gut microbes and sexual health, and is founded on preliminary evidence illuminating the relationship between the two. Indeed, researchers have already begun to explore strategies to leverage the gut-brain-axis in order to combat sexual dysfunction and improve overall sexual health and satisfaction.

Low desire and microbiome balance (females)

In a 2021 case-controlled study published in the Journal of Medical Internet Research¹, scientists investigated the relationship between specific microbes, serotonin levels, and the loss of sexual desire.

In the study, samples collected from 24 women with hypoactive sexual desire disorder (HSDD) and 22 healthy controls were analyzed using RNA gene sequencing and metabolome analysis. Results revealed altered metabolic signatures and bacterial composition in HSDD women, compared to control subjects.

In particular, HSDD women had a decreased amount of sex-drive associated Ruminococcaceae species and disproportionately elevated levels of specific species of lactic-acid-producing bacteria (LAB).

Notably, it is well established that certain LAB bacteria, such as some strains of Bifidobacterium, are associated with increased levels of kynurenic acid and tryptophan. These serotonin precursors are important for mood stability. Clinical research has also revealed enhanced serotonin as an important treatment for reducing anger, depression, and stress. However, excess serotonin can also suppress libido and sexual excitement—which is one of the most common side-effects of antidepressant medications. Finding the right balance of gut microbes and neurotransmitters appears to play an important role in maintaining a healthy sex drive.

Erectile dysfunction and microbiome diversity (males)

Data suggest that approximately 52 percent of men experience some form of erectile dysfunction (ED). Researchers conduced a study reported in Translational Andrology and Urology⁷aimed at identifying whether or not there may be a correlation between gut microbiota diversity and the development of ED.

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In this work, samples were collected from 30 patients with ED and 30 control subjects for analysis using rRNA gene sequencing. The results revealed that ED subjects had significantly lower gut microbial diversity compared to controls.

“Gut microbiota can regulate male erectile function by regulating hormone levels, inflammatory mediators, and other factors,” the authors report.

They asserted that normal erectile function is affected by an interplay between sex (and non-sex) hormones, emotional well-being, neurological factors, inflammation, and other factors related to environment, genetics, and social dynamics. As you may know, gut microbes can impact all of these factors.

Less than Satisfied

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All things considered, it is clear our bugs play a role in both libido and sexual function, but how did this relationship develop?

Our next blog post will explore the co-evolution of our gut microbes and human sexual health, with emphasis on microbiome hacks that may help optimize the system.