Gut microbiota dysbiosis in PCOS patients causes insulin resistance and hyperandrogenism through endotoxemia (LPS leakage), altered short-chain fatty acid production, and bile acid metabolism disruption.

Tremellen et al. proposed a hypothesis called DOGMA (dysbiosis of gut microbiota), which explains a possible sequence of events in the pathogenesis of PCOS as follows: 1) Obesity or high sugar, high-fat and low dietary fiber diet causing imbalance on intestinal flora, thus destroying connection between intestinal epithelial cells, which increases permeability of the gut mucosal; 2) Leaky gut may perhaps cause leakage of lipopolysaccharide (LPS) into systemic circulation, and the resultant activation of the immune system might interfere with functioning of insulin receptor, causing IR; 3) IR/Hyperinsulinemia might promote synthesis of testosterone, hence meddling with follicular development