Now the skin doesn't actually produce a hormone directly. What it does is it produces a pre hormone, a molecule that eventually is used to form a hormone. In fact, we produce this molecule inside the skin known as our cola calciferol, that is eventually used to produce calcitriol. So basically, inside our skin cells we use UV radiation. So the energy that comes from UV radiation to basically transform colicalcipheral, or actually to form colicalcipherel. And then the colicalcipheral, which is basically vitamin D, travels into our liver.