Despite that there has been no absolute cutoff regarding the benefits or harm of the acute or chronic L-Arg supplementation in CKD (Peters et al., 1999; Cross et al., 2001; Düsing et al., 2021), L-Arg deficiency is becoming a leading factor for eNOS deficits, and its substitution can show some positive CV effects in renal insufficiency (Amador-Martínez et al., 2019; Düsing et al., 2021; Hsu and Tain, 2021). The gene discussed is NOS3; the disease is chronic kidney disease.