I could understand why anti-aromatise's lower it because you lower estrogen production and the less igf-1 you produce as well as lowering the receptors sensitivity to igf-1. Now why would nolvadex lessen it? It still allows the body to aromatize test and various other steroids into estrogen so it still is in the system. I know it competes(blocks) with the estrogen receptor in tissues but also goes through in others. Does it somehow have a negative impact in the receptors of the liver hence lower igf-1 levels? Also why does aromasin not lower igf-1 production? It blocks estrogen so...... It should lower it yes?