Nope, and - yes.

( within the circle goes yet another circle, and within that one, oliver begins drawing a sigil. )

Human bodies carry a small amount of iron within them. Right? And metals are great for creating charms, especially protective ones. Unfortunately for me, I lost most my shit somewhere between falling asleep on Pierce's couch and waking up here. And generally, you want to stick with metals already touched by magic. Makes it easier. So I'm leeching just a tiny bit off you. I'll show you.