The Hair Growth Cycle

You’ve got hair — but have you ever stopped to think about how it grows? What causes our hair to squeeze out of our scalps like a Play-Doh spaghetti maker? Today, we’re going to take a look at the ins and outs of the hair growth cycle to learn more!

How Does Hair Get There?

Hair grows out of the root — called a follicle — just underneath the surface of the scalp. The follicle consists of two parts: the bulb and the papilla. The former holds all the cells that cause growth, and the latter supplies the blood to keep it all healthy. As the hair cells rapidly divide, the shaft forms and grows out of the follicle — that’s the strand we think of when we see the word hair! Eventually, the hair separates from the papilla and will fall out so new hair can grow in its place. This phenomenon happens in four stages — let’s take a deeper look at them now!

Stage 1 – The Anagen Phase

This phase is when your hair grows! The cells down in the bulb are doing their thing, dividing rapidly, while the papilla provides the necessary nutrition to keep that process rolling along smoothly. The anagen phase lasts anywhere between 2 and 7 years, and during this time, hair can grow to an average of 18-30 inches long, depending on genetics and other factors.

Stage 2 – The Catagen Phase

This period only lasts about 2-3 weeks on average and is the point at which the bulb and papilla detach from the shaft. Without the proper blood supply to deliver nutrients and oxygen necessary for growth, the strand dies. This particular strand does not grow any longer — it is on the way out!

Stage 3 – The Telogen Phase

The telogen phase is when the dead hair strand gets to rest in peace for a little while! After detaching from the papilla, the shaft sits in the scalp while new hair begins growing in the bulb below. This process takes about three months.

Stage 4 – The Exogen Phase

Now the strand takes its final bow and exits the scalp, stage left. The new hair in the bulb below will begin to push out of the scalp and loosen the existing strand. Once loose, it will naturally fall away, or you will brush it out when you comb your hair. The average person loses between 50 and 150 strands of hair a day during this phase! Wow.

That’s the hair growth cycle! How long does it take for your hair to grow? Does it take two years, or is it closer to seven? Do you ever count the hair you lose in a day? We want to know! Tell us in the comments!