I believe Marshall was trolling reporters when he said this.

“I don’t know too much about Adderall,” Marshall said. “I know guys, it is such a competitive league, guys try anything just to get that edge. I’ve heard of some crazy stories. I’ve heard (of) guys using like Viagra, seriously. Because the blood is supposedly thin, some crazy stuff. So, you know, it’s kind of scary with some of these chemicals that are in some of these things so you have to be careful.”

Then again this is Brandon Marshall, so who knows.

I am not a doctor or anything, but I think Viagra would slow down your effectiveness and range of motion, if you get what I am saying.  Because it it is hard to run with a …you know never mind.