I read most of this article because my last physical over a year ago showed mildly diminished kidney function. E-gfr of 58. I wanted to try John's lysine vitamin c protocol, but read somewhere that lysine was rough on kidneys. I've been taking for about 10 days supplemental l-citrulline. Now it seems like excessive arginine/NO from the citrulline is a problem. So confused. Anybody have any recommendations or additional sources? I'd greatly appreciate the help.