Symmetric dimethylarginine (SDMA) is one of the byproducts of protein methylation, and it has been previously identified as an independent cardiovascular risk factor in patients with chronic kidney disease. The majority of SDMA is excreted through renal tubules; however, its effect on kidney in pathological conditions is not fully understood. In a recent study, researchers from Shuguang Hospital aimed to investigate the role of SDMA in renal tubulointerstitial fibrosis.