Facial hair growth is a sign of puberty in boys. It usually begins to appear around age 12. The first hair may appear on the upper lip, chin, or sideburns. The hair is usually thin and light-colored at first. As boys go through puberty, their hair becomes coarser, thicker, and darker. Most boys will have a full beard by age 17 or 18. Facial hair growth is controlled by hormones. Testosterone is the hormone that makes facial hair grow. Boys who have more testosterone in their bodies will usually grow facial hair sooner and have more facial hair than boys with less testosterone. There is nothing a boy can do to make his facial hair grow faster. Some boys shave their facial hair as soon as it starts to grow in. Others wait until it is thicker before they start shaving. Some boys never shave their facial hair and let it grow into a beard.