Dr. Kim Capone, Lead educator of IVH and Chief Science Officer for Vaginal Biome Science.
Since February is the month of love, let’s explore an unexpected matchmaker in human relationships—the microbiome. While we often think of attraction as a mix of chemistry, personality, and looks, current research suggests that our microbiome may play a hidden role in who we’re drawn to and how we experience intimacy.
The Microbiome’s Role in Attraction
Physical appearance, scent, and subconscious hormonal cues all play a role in mate selection. Evolutionary biology suggests that humans tend to choose partners who signal health and fertility—qualities that enhance reproductive success. Current research shows that our microbiomes contribute to these signals, affecting body odor, immune compatibility, and even libido.
The "Scent of Love": How Microbes Influence Attraction
The human sense of smell is a powerful driver of attraction. The major histocompatibility complex (MHC) is a set of immune system genes that affect body odor, which is shaped in part by bacteria on our skin. In the well-known T-shirt experiment, men wore the same shirt for two nights, and women rated their scent. The results? Women were more attracted to the scent of men with MHC genes different from their own, a mechanism that may promote stronger immune diversity in offspring. The bacteria on our skin and in our sweat glands help create these odor cues, meaning that microbial composition contributes to natural scent and may influence attraction at a subconscious level.
The Vaginal Microbiome & Intimacy
Beyond gut and skin bacteria, the vaginal microbiome plays a significant role in sexual health and comfort. A balanced vaginal microbiome is typically dominated by Lactobacillus species, which help maintain an acidic pH and protect against infections. However, disruptions in the vaginal microbiome such as bacterial vaginosis (BV) or yeast overgrowth can impact intimacy by causing vaginal dryness, discomfort, and pain, as well as changes in vaginal odor that can all lead to lack of sexual desire. Maintaining a healthy vaginal microbiome supports sexual comfort, confidence, and overall well-being which in turn can positively impact intimacy and relationships.
The Love Hormone & The Microbiome: How Gut and Vaginal Bacteria Impact Libido
Oxytocin, known as the “love hormone”, is released during moments of bonding, such as kissing, cuddling, and sex. Research suggests that a balanced gut microbiome may help regulate oxytocin production, influencing mood and social bonding. Likewise, probiotic supplementation in mice has been linked to increased oxytocin release, greater confidence, and improved social behavior. Taken together, the evidence suggests that microbial health plays a role in overall well-being, so by taking care of your microbiome, you're not just supporting your physical health—you’re also nurturing confidence, comfort, and connection in your relationships.
This Valentine’s season, show yourself some love from the inside out—because when your microbiome thrives, so do you.
References
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- Lindholm AK, Dzuik SK, White DJ, et al. The influence of gut microbiota on mate choice in mice. Front Microbiol. 2022;13:916766. Frontiers
- Onderdonk AB, Delaney ML, Fichorova RN. The human microbiome and bacterial vaginosis. Research in Microbiology. 2016;167(7):463-472. NCBI
- Sharon G, Segal D, Ringo JM, et al. Commensal bacteria play a role in mate choice of Drosophila melanogaster. Proc Natl Acad Sci U S A. 2010 Nov 16;107(46):20051-6. NCBI
- Wedekind C, Seebeck T, Bettens F, Paepke AJ. MHC-dependent mate preferences in humans. Proc Biol Sci. 1995 Jun 22;260(1359):245-9. Royal Society