When we look at our hair and see the scalp showing through, many of us panic. We want to know what’s happened to our hair, and, even more importantly, is our hair going to grow back. Hair grows from the follicles on our head, so it makes sense to know if those follicles are still alive and capable of producing hair.

But what are hair follicles anyway? Essentially, a follicle is a cell-lined sac from which strands of hair grow. Oil glands called the sebaceous glands are attached to the follicles and produce a fatty substance called sebum that climbs up the follicle to our scalp. There the sebum oils our skin and hair.

But when hair follicles don’t get enough nourishment, they can die. They simply become thinner and thinner until they eventually fall off our heads. When this happens, our scalp loses hair and we see baldness.

But when our hair thins out this doesn’t necessarily mean our hair follicles are dead. Sometimes, for many different reasons, our hair follicles go into a resting phase and new hair growth temporarily stops. In the hair cycle, there’s a resting phase called the telogen phase. But in this phase, while the old hair rests, new hair begins to grow. Therefore, even if our hair is this resting phase, hair is still growing. When hair follicles die, however, hair growth stops completely.

To know if your hair follicles are still active, just take a look at the scalp on your head. If you see any hairs on your scalp—no matter how sparse, thin, short or fuzzy—your hair follicles are still alive and kicking and sprouting new hairs.

Click to learn more about the hair cycle and hair growth.