Your Hair’s Natural Growth Cycle

There are three phases of hair growth: anagen, catagen and telogen. At any given time, a random number of hairs will be in one of these three phases of growth. To better understand the hair growth cycle and how it relates to hair loss, it helps to start with the anatomy of hair.

The Anatomy Of Hair

Hair fibers are primarily composed of a protein called keratin and grow from hair follicles in the skin. At the base of each hair follicle is a living bulb. Inside the bulb, active cells divide and grow to create hair. Blood vessels provide nourishment for the bulb and deliver hormones that impact hair growth.

The Three Phases of Hair Growth

Everyone’s hair growth is unique, but the average rate of growth is about six inches per year. As hair grows, individual strands randomly cycle through these phases of growth:

Anagen (growth phase): As many as 85-90% of the hairs on your head are growing at any given time and each hair is in the anagen phase for several years.

Catagen (transitional phase): Over the course of a few weeks, hair growth slows as follicles shrink.

Telogen (resting phase): For a period of months, hair stops growing and detaches itself from the hair follicle. When this happens, a new hair starts its growth phase and pushes the old hair out, which is why we typically shed 50-100 hairs a day.

Disruptions in Hair Growth

Numerous contributing factors can impact hair growth, but by far the most common reason for thinning hair is androgenetic alopecia, better known as male pattern baldness and female pattern baldness. Men and women with androgenetic alopecia have inherited hair follicles that are sensitive to dihydrotestosterone (DHT). DHT causes hair follicles to miniaturize over time producing thinner and finer hair. Eventually, the follicles stop producing terminal (normal, thick) hairs and grow only miniaturized (“peach fuzz”) hairs. For this reason, hair loss is progressive.

For more information about other hair loss conditions, click here.

For informational purposes only. The exact cause of hair loss can only be determined by a medical professional.