Strands of hair from your head grow from your hair follicles, which are cell-lined sacs. Sebaceous oil glands attach to the follicles, which produce sebum. Sebum then climbs up the follicle to reach your scalp. Sebum thereafter goes about naturally oiling your hair and skin. If you're experiencing a lack of healthy hair growth, you need to learn whether your hair follicles are indeed alive and are capable of producing hair.