I have a friend who actually also suffers from Nephritis and he has taken AS before on an off. Me personally I wouldn’t risk it unless I had a doctors approval and he monitored my blood and urine I would say No. Keep in mind that nephritis is at its highest risk when your increasing your protein, potassium and sodium. All things a body builder needs to make gains and replace electrolytes. So not only would most AS's cause stress, but the increase in protein and potassium’s along with day to day stress would also add to the Russian roulette factor. If your friend is old enough he can visit a hormone doctor and complain about low sex drive, stress, problems sleeping, erection problems and they can order some test transdermal or inj. and monitor him. HGH can help improve the situation with improved immune system and over all organ tissue repair. But it still depends on the severity and I would seek out the right doctor not a forum.