What Are the Four Stages of the Hair Growth Cycle?

You probably know that your hair grows and falls out on a regular basis. What are you aware of the four distinct stages that make up the hair growth cycle: anagen, catagen, telogen, and exogen?

Let’s take a closer look at each one of these stages.

Anagen: The Growth Phase

The anagen stage is the growth phase of the hair cycle. It can last anywhere from 2-8 years, and during this time, your hair will grow about 1 cm per month. This is the longest stage of the hair cycle, and it’s determined by your genes.

Of all the hair growth phases, anagen is the most important because it’s when your hair follicles are actively growing hair. If your anagen phase is shorter, your overall hair length will be shorter; if it’s longer, your hair will be longer.

At any given time, around 85% of scalp hair is in the anagen phase.

Catagen: The Transition Phase

The catagen phase is the transition phase of the hair cycle, and it lasts for about 2 weeks. During this time, your hair follicle shrinks and detaches from the blood supply. This phase marks the end of the growth period and is followed by the resting phase.

About 3% of hair follicles are in the catagen phase.

Telogen: The Resting Phase

The telogen stage is the resting phase of the hair cycle, and it lasts for about 2-4 months. During this time, your hair follicle remains inactive and there is no new hair growth.

Telogen is particularly relevant in hair loss research because it’s the phase during which your hair begins to fall out.

Around 10-15% of follicles are in the telogen phase.

Exogen: The Shedding Phase

Sometimes grouped in with the telogen phase, exogen is a mini-phase that occurs at the end of the resting phase. It lasts for about 2 weeks, and during this time, your hair follicle pushes the old, dead hair shaft (known as a club hair) out and makes room for new growth. As hair shedding occurs, the follicle returns to the anagen phase and begins growing new hair.


So there you have it – the four stages of the hair growth cycle! Keep in mind that this is a continuous cycle, and each strand of hair goes through these phases at different times (that’s why you don’t lose all your hair at once). This is a normal process, and everyone sheds around 50-100 hairs each day.

Keep in mind that these phases vary wildly when it comes to the rest of the body. Facial hair, for example, has a much shorter growth phase than scalp hair. Eyelashes have the shortest growth phases, while the hair on your legs and arms falls somewhere in-between.

How does the hair growth cycle relate to hair loss?

The hair growth cycle is important to understand because it can help explain why and when you may experience hair loss. For example, if you are experiencing telogen effluvium (a type of temporary hair loss), it is likely due to an increased number of hairs in the telogen phase. This can be caused by a variety of factors, such as stress, illness, or medication.

While the hair growth cycle is a natural process, it can be disrupted by various factors, which can lead to hair loss. Healthy hair growth can be disrupted, leading to hair follicles that enter the telogen phase too early, which can result in hair thinning or baldness.

There are many factors that can disrupt the hair growth cycle and cause hair loss, including:

What is hair?

Your hair is made up of two parts – the shaft and the root. The shaft is the visible part of your hair that extends from your scalp. The root is the part of your hair that is beneath the skin and is not visible.

The shaft is made up of three layers – the medulla, the cortex, and the cuticle. The medulla is the innermost layer of the hair shaft and is made up of soft, spongy cells. The cortex is the middle layer of the hair shaft and is made up of long, protein fibres that give your hair its strength and elasticity. The cuticle is the outer layer of the hair shaft and is made up of a thin layer of cells that overlap each other like tiles on a roof.

The cortex makes up the majority of the hair shaft and is responsible for the colour, texture, and strength of your hair. The medulla is present in some types of hair, but it is not necessary for the hair to be healthy. The cuticle is a protective layer that covers the cortex and medulla and helps to keep your hair shaft intact.

Hair follicle

Hair is made up of a protein called keratin. This protein is produced by cells in the hair follicle, and it is what gives your hair its structure. As the cells move up the hair shaft, they harden and die in a process called keratinization.


What percentage of hair follicles are in each of the phases?

At any given time, about 85% of your hair is in the anagen phase. Around 3% of your hair is in the catagen phase, and about 10-15% of your hair is in the telogen phase.

How long does it take for new hair to grow?

Hair typically grows at a rate of around 1 cm per month. The speed at which your hair grows depends on a variety of factors, including age, genetics, hormones, and health.

What is the normal shedding rate?

Most people lose around 50-100 hairs each day. This is considered to be a normal shedding rate, and it usually doesn’t cause noticeable hair loss. If you are losing more than this, it may be a sign of a problem.

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