Abstract
We propose the term testobolome, analogous to the estrobolome, to describe gut bacteria that metabolize testosterone. Testosterone undergoes microbial transformations similar to estrogens, potentially influencing host hormone homeostasis and health. This review defines the testobolome, identifies its known members, and explores mechanisms that are shared or distinct from the estrobolome. We outline a framework for future research into microbiome-mediated steroid metabolism, including its role in aging and hormone-driven diseases.