The Science of Hair Growth (Made Simple)

According to WebMD, hair is made up of keratin, protein, which is produced in hair follicles. As follicles produce new cells, the old cells are pushed out through the surface of the skin at around 6 inches per year.

You may call this the growing of hair.

But in fact, a strand of hair you see is a string of dead keratin cells.

The average adult head has 100,000 to 150,000 hairs and loses up to 50-100 hairs per day. So if you're losing up to 100 hairs per day, you shouldn't be worried.

There are other solutions that can promote hair growth, but for now, just take look at the hair growth cycle.


Understanding The Hair Growth Cycle

There are three stages of a hair growth cycle: anagen, catagen and telogen.

Here's a video that simply illustrates the hair growth cycle:


The Anagen phase has active hair growth that lasts from 2-7 years. Your hair is in the anagen phase 85-90% of the time. When you're growing older, this stage becomes shorter and thus cause thinner hair over time.

The longer the anagen phase, the longer your hair will grow. The hairs on your arms, eyelashes and legs have a much shorter anagen phase of 30-45 days and that's why they're much shorter than your head hair


At the Catagen phase, this is where transitional hair growth exists which lasts for 2-3 weeks. In this stage, the follicles are detached.


The resting phase of the Telogen stage lasts for 2-3 months. After which, the hair sheds and a new hair is replaced, and so the cycle restarts again. As it is already detached, hair can appear dull and can't be repaired.

Important Note: Hair loss happens when there are disruptions in the hair growth cycle due to a multitude of reasons. I'll cover the most common one in a while.​

Question: how extensive do you think hair loss is?

Answer: With a population of 325 million in the United States, a whopping 56 million are suffering from hair loss.

Meaning, every six people you meet, one has a problem with losing hair.

This is alarming yet a common occurrence.

To further break it down, out of these 56 million sufferers, 35 million are males and the rest of the 21 million are females.

Have you ever wondered why are there so many people having this issue?

I'll come to that answer in a while.

There are different terms for hair loss. You can call it alopecia, balding, etc. They all roughly mean the same thing.

There is but one term that you must know..

Androgenetic/Androgenic Alopecia

Also known as Male-Pattern Baldness or Female-Pattern Baldness.

This is the most common type of hair loss and chances are you're in that category (same with me).

And how did this come about? It's mainly due to genes passed down from your parents or close relatives (oh, don't we love to blame them).

The signs of this happening are pretty clear.

For males, you'll start with a higher forehead, leading to a receding hairline progressing to a 'M' shape pattern. Another sign is thinning at the crown area and gradually spreading.

For females, you won't experience the same signs with men. Thinning takes place all around the scalp.

So how exactly does this happen?

Researchers have determined that pattern baldness is caused by a particular androgen called Dihydrotestosterone (DHT).

Increased levels of DHT cause a shorter hair growth cycle which in turn causes shorter and thinner hair strands. Furthermore, there will be an increase in delay in replacing hairs that are shed.

This is the very reason why solutions catered to hair loss are geared towards reducing or blocking the DHT.


The information in this article is condensed and made extremely simple for your easy consumption. Hopefully, it has shed some insights that you've never known before. It's important to understand how hair growth works before you take measures to combat hair loss.​

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