Its a myth, brother. Only 17aa compound may cause liver toxicity when we talk about steroids. By the way, tren isnt a threat to kidney. Its just a misconcept created by some users, because the urine get too dark when they use tren. Its pretty normal since tren is very hard to be metabolized, and when its get into urine the metabolites of tren still has the caracteristic colour (brown). So some guys take this fact by kidney toxicity, but it is another myth.