4 phases of the hair growth cycle

Did you know which cycles your hair goes through? Most healthy men and women have 80,000 to 120,000 terminal hairs on their scalp.

The whole cycle lasts for a few years for each of your hair strands on the scalp. Let’s look deeper into those phases.

The hair growth happens in a cyclical process in your hair follicles. The cycle consists of four phases:

  1. Anagen (growth)

The phase in which your hair starts growing from the follicle root is called the Anagen phase. During anagen, the stem cells of the dermal papilla multiply to produce hair protein and fibers. This is the ACTIVE GROWTH phase of hair follicles and lasts 2-7 years (sometimes even longer) . During this phase, hair grows about 1-2 cm every 28 days.

Anagen Effluvium

Sometimes, external factors like chemotherapy drugs, radiotherapy, oral contraceptives, vitamin A poisoning, chronic infections, other chemicals, etc. can result in an abnormal ending of the anagen phase. This means your hair starts to shed when it is still in the anagen phase. This condition is termed as ‘Anagen Effluvium’.

  1. Catagen (regression/transition) 

At the end of the Anagen phase, your hair strand enters the catagen phase naturally during which the hair follicle shrinks and detaches from the dermal papilla (the structure that supplies blood to the hair follicle). This is the transition or regression phase of your hair growth.This phase lasts 2-3 weeks.

DID YOU KNOW – At any given time, around 1% of your hair can be in the catagen stage on your scalp.

  1. Telogen (rest)

This is also known as the RESTING PHASE. During the telogen phase, the hair follicle remains club and dormant resting phase, telogen begins while new hair starts to grow beneath it.

A CLUB HAIR IS a normal, fully formed strand that has stopped growing. It’s named for the bulbous, club-like appearance at the end of the hair where keratin has built up. Club hairs appear in the catagen phase of the hair growth cycle, which is a transitional phase between growth and resting (Hoover, 2021).

Telogen phase lasts for 3-5 months during which a new hair emerges from the roots and slowly pushes up the previous club hair.

Telogen effluvium

Sometimes, conditions like emotional and physiological stress,hormonal imbalances caused by pregnancy or menopause, protein deficiency, etc. can result in the hair prematurely entering the telogen phase, and eventually shed off. This kind of hair loss is called Telogen effluvium 

Telogen effluvium is one of the most common causes of alopecia. It is a scalp disorder characterised by excessive shedding of hair.
(Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus. 2020 May 27;12(5):e8320. doi: 10.7759/cureus.8320. PMID: 32607303; PMCID: PMC7320655.)

  1. Exogen (shedding) 

This is the final stage of the hair growth cycle. During this phase, the old hair strand completely detaches from the scalp and sheds off and the new hair begins to emerge from the scalp. This is the hair that you notice falling out while you comb or brush every day as around 50-100 strands undergo exogen phase daily naturally.

Sometimes a fifth phase is also mentioned – called the shedding phase. This phase occurs when the old hair sheds, and the new hair begins to grow in the anagen phase again – thus the hair cycle starts all over again.

Each hair goes through the hair growth cycle at different times, which is why we don’t lose all of our hair at once. 

What is the normal amount of hair to lose daily?

It’s normal to shed between 50 and 100 hairs a day. Telogen effluvium causes about 300 hair strands to fall off in a day. When the body sheds significantly more hairs every day, a person has excessive hair shedding. The medical term for this condition is telogen effluvium.


  • Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus. 2020 May 27;12(5):e8320. doi: 10.7759/cureus.8320. PMID: 32607303; PMCID: PMC7320655.
  • Bernard BA. Advances in Understanding Hair Growth. F1000Res. 2016 Feb 8;5:F1000 Faculty Rev-147. doi: 10.12688/f1000research.7520.1. PMID: 26918186; PMCID: PMC4755418.
  • Anatomy, Hair Follicle – Julianna L. Martel; Julia H. Miao; Talel Badri.
  • https://www.ncbi.nlm.nih.gov/books/NBK513312/

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