What is more commonly used for putting on muscle mass...Density or Mass Aminos? I read that the Mass Aminos are most commonly used for putting on size in combo with the Ultra 40. I guess the Density is one of the newer products, so how popular is that?

Since your goal is to put on size, Density would be ok, but MASS would be way better! Mass in conjunction with Ultra40 is the Ultimate Beverly stack. 4 of each with every meal and watch yourself harden up and GROW!

Of course, you diet better be pretty good too...

Try adding creatine selectas well I swear by it