Every system in our body is connected, and every process in it is affected by all others. When two processes affect each other in a bidirectional manner, they are called axes. Scientists have recently looked into the gut-skin-brain axis, or the connection between your gut and skin health and your psychological well-being.
It is commonly known that your gut has its own microbiome, consisting of bacteria that help us digest our food. Less people know that there is a similar microbiome on your skin. Right now, there are thousands of different species of bacteria, fungi, viruses, and other microorganisms living in symbiosis on the surface of your skin. The word microbe usually comes with a negative connotation, making you think of disease or parasites, but the microbes both on our skin and in our gut are vital to our health. Having an unbalanced gut microbiome, or being in dysbiosis, is often associated with various skin conditions, such as eczema, psoriasis, rosacea, or acne (Wiginton 2025).
The skin makes for a very harsh environment. It is dry and we are constantly shedding skin cells, which makes it a less than ideal place for a microbe to live. But many species have adapted to be able to handle life on the skin, and most have preferred locations on the body as well. Some bacteria prefer somewhere warm, such as the armpit or foot, whereas others thrive somewhere oily, like our face. These microbes actually work as part of our immune system. Our skin is our largest organ and prevents pathogens from entering our body. The microbes that thrive on our skin like the harsh environment, and help keep it so. Other harmful microbes often cannot survive in these conditions, and sometimes are even attacked by our skin’s microbes (Byrd et al. 2018).
The link between the gut microbiome and our psychological well-being has been well established as bidirectional, meaning they affect each other. Dysbiosis, or an imbalance, in the gut has been linked to depression, anxiety, and autism. On the other hand, stress can alter our gut microbiome and make us more susceptible for gastrointestinal disorders. Studies have even shown which bacteria, Cutibacterium, show the strongest link to our psychological well-being (Tyson-Carr et al. 2025).
Recently, proof has been found of a triple axis, the gut-skin-brain axis. Probiotics are living microorganisms in our gut and have been found to play a part in our immune system. These microbes in the gut help our immune cells distinguish between harmful and beneficial microorganisms. Bacteria in the gut also release molecules that have anti-inflammatory effects on the skin. Studies have shown that taking probiotics benefits your gut microbiome, which in turn benefits our immune system, creating a snowball effect that can be beneficial towards our skin health and psychological well-being. Probiotics have even been proven to improve some chronic inflammatory skin diseases, such as psoriasis by increasing certain microbe species in the gut (Abdi et al. 2024).
Wiginton, K. (2025). What Is the Skin Microbiome? WebMD. https://www.webmd.com/skin-problems-and-treatments/skin-microbiome
Byrd, A. L., Belkaid, Y., & Segre, J. A. (2018). The human skin microbiome. Nature Reviews Microbiology, 16(3), 143–155. https://www.nature.com/articles/nrmicro.2017.157
Tyson-Carr, J., Leng, J., Scott, M., Adams, S., Hoptroff, M., Murphy, B., Fallon, N., Paterson, S., Thomas, A., Giesbrecht, T., & Roberts, C. (2025). Body site-specific associations between human skin microbiome composition and psychological wellbeing. British Journal of Dermatology, 193(Supplement 2), ii6–ii14. https://academic.oup.com/bjd/article/193/Supplement_2/ii6/8140349
Abdi, A., Oroojzadeh, P., Valivand, N., Sambrani, R., Lotfi, H. (2024). Immunological aspects of probiotics for improving skin diseases: Influence on the Gut-Brain-Skin Axis. Biochemical and Biophysical Research Communications, 702. https://www.sciencedirect.com/science/article/pii/S0006291X24001682
