Our understanding of the human microbiota and its interaction with our bodies has advanced dramatically in the past decade. It is becoming clear that the billions of microbes in our gut have a profound influence on human health and disease. Gaining a deeper understanding of how the microbiota interacts with human physiological systems, particularly through the metabolites it releases, is allowing researchers to develop novel treatments for a range of diseases. One such metabolite, 10-hydroxy-cis-12-octadecenoic acid (HYA), has been shown to have a potential role in type 2 diabetes and inflammatory bowel disease, both of which affect millions worldwide. Isolating this molecule and demonstrating its potency was no easy task, but the research team at Noster in Japan took on that challenge. The next hurdle is to demonstrate its efficacy in a clinical setting—a critical step that is already underway.