One of those functions is helping you grow hair. Pay attention to your diet, and make sure that you're getting enough.
The biggest mistake many beard-growers make is calling things off too early. Not all facial hairs grow at a similar rate, so you won't know the full extent of your.
Men that can't grow a beard, or can grow just a little amount of facial hair have low levels of these two hormones so they can't stimulate beard.