What Is the Hair Growth Cycle? How Anagen, Catagen, and Telogen Phases Control Hair Loss2026.05.04

“I’m losing more than 100 hairs a day.” “Every time I shampoo, I see alarming amounts of hair falling out.”

If these concerns sound familiar, you are far from alone.

But here is an important fact: losing 50 to 100 hairs per day is entirely normal.

The real question is not about quantity — it is about quality: whether the hair that falls out is being replaced through a healthy cycle.

The concept at the heart of hair health is the hair growth cycle, also known as the hair cycle.

What Is the Hair Growth Cycle?

The hair growth cycle is a biological process in which each individual hair follicle continuously repeats a cycle of growth, regression, rest, and renewal.

Every hair on the body operates on its own independent rhythm — and scalp hair has one of the longest cycles of all.

It is precisely this repeating mechanism that allows our hair to maintain a consistent density and length throughout our lives.

The hair cycle is divided into three main phases:

・Anagen (growth phase): Hair matrix cells divide actively and the hair grows longer.

・Catagen (regression phase): Cell division stops and the hair root contracts and detaches.

・Telogen (resting phase): The follicle enters a dormant state before the old hair sheds naturally.

When these three phases function normally, healthy hair density is maintained.

Anagen — The Growth Phase

Anagen is the longest and most critical phase of the hair cycle.

For scalp hair, it typically lasts two to seven years.

During this period, the hair matrix cells at the base of the follicle — surrounding the dermal papilla — divide and multiply actively, growing the hair approximately one to one and a half centimeters per month.

In a healthy scalp, approximately 85–90% of all hairs are in the anagen phase at any given time.

The longer the anagen phase, the longer and thicker the hair can grow.

In conditions such as AGA, the shortening of anagen is one of the primary mechanisms driving progressive hair thinning.

Catagen — A Brief Transition of Two to Three Weeks

Catagen is the transitional phase between anagen and telogen.

It is remarkably brief — lasting only about two to three weeks.

During catagen, hair matrix cell division ceases, and the hair root detaches from the dermal papilla and moves upward as the follicle shrinks.

Hairs in catagen take on a characteristic form known as a “club hair.”

Only about 1–3% of scalp hairs are in catagen at any given time, so this phase is rarely noticeable.

Abnormal prolongation or shortening of catagen can disrupt the overall balance of the hair cycle.

Telogen — Shedding and Preparing for the Next Cycle

Telogen is the phase during which the follicle rests completely and the formation of a new hair begins.

It typically lasts three to four months, ending with the natural shedding of the old club hair.

At the same time, the dermal papilla reactivates, and a new anagen phase begins.

In a healthy scalp, approximately 10–15% of hairs are in the telogen phase at any given time.

When an abnormally large proportion of hairs shift into telogen simultaneously, the result is a condition called telogen effluvium — a sudden, significant increase in hair shedding.

Postpartum hair loss and stress-related shedding are among the most common causes of telogen effluvium.

How AGA Disrupts the Hair Cycle

The hair cycle disruption seen in AGA is caused by the action of DHT (dihydrotestosterone).

DHT binds to androgen receptors in the dermal papilla, suppresses hair matrix cell division, and shortens the anagen phase.

What was once a two-to-seven-year growth phase may be cut down to just a few months or a year — meaning the hair transitions into catagen and telogen before it has had time to grow properly.

Each time this abbreviated cycle repeats, the follicle miniaturizes further, eventually atrophying completely.

Regenerative medicine aims to restore the shortened anagen phase back toward its natural length.

Restoring the Hair Cycle Through Regenerative Medicine

At AVAN TOKYO Ginza Hair Regeneration Clinic, we combine stem cell conditioned medium, exosomes, and Morpheus8 to take a comprehensive approach to restoring disrupted hair cycles at their root.

Stem cell conditioned medium — containing growth factors such as EGF, FGF, and VEGF — has been shown to directly stimulate dermal papilla cells and extend the shortened anagen phase.

Understanding why hair falls out is the first and most important step toward choosing a treatment that truly works.

📍AVAN TOKYO Ginza Hair Regeneration Clinic

AVAN TOKYO GINZA HAIR REGENERATION CLINIC

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