Arnold use tons of dbol, primo, and deca. It really does not matter though. You could use what he used in 10x the dosage and you'll never, ever look anything close to him. His physique and genetics were 1 in a billion and nothing like his proportions and symmetry will ever be seen again. Just take his calves and biceps. All the GH, test, slin, etc that's used today, Arnold's biceps were still the best ever. It's just genetics. He didn't train harder than Ronnie, Jay, Gustavo or anyone else. The insertions on his body gave him those bulging, peaking biceps. And fwiw I think his chest was also the best ever. No secrets there either, lots of presses, flyes, and dips. And again, those genetics.