I did an interview with Jerry Brainum for my podcast Bodybuilding Legends and he said Arnold was taking the same drugs as everyone else but he just responded to them way better. He was he was very open about what he was taking and he even gave shots to other guys he trained with at his house but no one responded to the drugs like he did. Except Danny Padilla, Jerry said he saw Danny come to California at the beginning of the summer and he was small and smooth. After he started training and getting on a cycle, within weeks he would totally transform his body by adding lots of muscle and losing fat at the same time.