Do you know that your hair is often considered a remnant of the animal mane? Your hair has a social role (a symbol of youth, health, and fertility) and a biological role. They protect the top of your head from the sun. It is the hair follicle that anchors your hair, this super important structure.
Your hair has a unique feature for each individual. Surprisingly, it is estimated that adults have more than 5 million hair follicles, with 1 million hair follicles found only on your head.

According to the American Academy of Dermatology, about 120,000 to 150,000 hair follicles cover your entire scalp. Depending on the scalp region, the density of these hair follicles varies from 200 to 300 follicles sq cm.
Interestingly, you naturally shed a hundred hair follicles each day. The speed of your hair growth is about 0.3 mm per day or 12 cm per year. Your hair speed growth is affected by numerous factors. It depends on factors like follicle location, age, gender, and ethnicity of the individual, and environmental factors.
How Does a Hair Follicle Function?
Hair follicles are small, pocket-like holes all over your skin. As the name suggests, they grow hair.
According to the American Academy of Dermatology, the average human has more than 100,000 hair follicles on the scalp alone. Read below to learn more about what hair follicles are and how they grow hair.
Hair has a simple structure but has important functions in social functioning. It is made of a tough protein called keratin. A hair follicle is responsible for anchoring each hair into your skin.

The hair bulb forms the base of your hair follicle. In the bulb, living cells divide and grow to build the hair shaft. Blood vessels around the area nourish the cells in your hair bulb. The blood vessels also deliver hormones that modify the hair growth cycle and structure at different times of life for different people.
Anatomy of a Hair Follicle
Your hair follicle is a tunnel-shaped structure in the epidermis or outer layer of your skin. Hair starts to grow at the bottom of a hair follicle. Your hair root is made up of protein cells and blood from the surrounding blood vessels nourish these cells.
As more cells are created in the area, the hair grows out of your skin and reaches the surface. Sebaceous glands located near the hair follicles produce oil, which nourishes the hair and skin.
Hair Follicle Growth Cycle
Your hair grows out of the follicles in cycles. The hair growth cycle has three different phases:
- Anagen (growth) phase. In this phase, your hair begins to grow from the root. This phase usually lasts between three to seven years.
- Catagen (transitional) phase. During this phase, your hair growth slows down, and the hair follicle shrinks in this phase. This phase lasts between two and four months.
- Telogen (resting) phase. The old hair falls out at this age, and new ones begin to grow from the same hair follicle. This lasts from three to four months.
Recent research suggested that hair follicles do not just rest during the telogen phase. A lot of cellular activity happens during this phase. The tissues regenerate and grow more hair during this period. In other words, the telogen phase is the crucial stage in the formation of healthy hair.

Different follicles on your skin go through different phases of the cycle at the same time. Some hair follicles are in the growth phase, while others might be in the resting phase. Some of your hairs might be in the growing stage, while others are falling out.
According to the American Osteopathic College of Dermatology, a person loses approx 100 strands of hair a day. Moreover, about 90 percent of your hair follicles are in the anagen phase at any given time.
The Life of a Hair Follicle
On average, your hair grows half an inch each month. Several factors decide your hair growth which could include age, hair type, and your overall health.
Hair follicles are not just responsible for how much your hair grows. They also influence what your hair will look like. The shape of your follicle actually determines how curly your hair is. Circular follicles produce straight hair, while oval follicles produce curlier hair.
Hair follicles also play a vital part in determining the color of your hair. Similar to your skin, your hair gets its pigment from the presence of melanin. The human body has two types of melanin: eumelanin and pheomelanin.
It is your genes that determine whether you have eumelanin or pheomelanin, as well as how much of each pigment you have. If you have an abundance of eumelanin, your hair is black in color, and a moderate amount makes your hair brown. In contrast, a very little eumelanin will make your hair blonde. Pheomelanin, on the other hand, makes your hair red.
This melanin is stored in your hair follicle cells. It then determines the color of your hair. With age, your follicles can lose their ability to produce melanin. As a result, you get gray or white hair.
If any hair is pulled out of the hair follicle, it can regrow after a few days. Your damaged follicle may stop producing hair. Conditions such as alopecia could cause your follicles to stop producing hair altogether.
Issues with Hair Follicles
You could have several hair conditions caused by issues with hair follicles. If you think you have a hair condition or notice unexplained symptoms like hair loss, it is best to consult with a dermatologist.

1 Folliculitis
Folliculitis is a disorder where there is an inflammation of your hair follicles. It can occur anywhere hair grows, including your scalp, armpits, legs, face, and arms.
Folliculitis often looks like small bumps or a rash on your skin. The bumps may be white, red, or yellow, and they often contain pus. Often, folliculitis is itchy and sore.
A staph infection often causes folliculitis. The condition can go away without treatment. But your dermatologist can diagnose and give you medication to help manage it. This could include topical treatments or oral drugs to treat the infection and soothe the symptoms.
2 Androgenetic Alopecia
Androgenetic alopecia, also known as the pattern baldness which is commonly seen in men. It is a condition that affects the growth cycle of hair follicles on your scalp.
The hair cycle slows down and weakens, eventually, the growth is stopped. Only solution left is hair transplant. As a result, they do not produce follicles, and hence no new hair grows.

According to the US National Library of Medicine, about 50 million men and 30 million women are affected by androgenetic alopecia disorder.
3 Alopecia Areata
Alopecia areata is an autoimmune disease. Your immune system mistakes the hair follicles for foreign cells and starts to attack them. As a result, your hair falls out in clumps.

This leads to a condition called alopecia universalis, which is a total loss of hair not only on your scalp but all over the body. No known cure exists for alopecia areata yet. But your doctor might use steroidal injections or topical treatments that can slow down hair loss.
4 Telogen Effluvium
Telogen effluvium is a common form of hair loss and is a temporary condition. A stressful event might cause your hair follicles to go into the telogen phase prematurely. This causes your hair to thin and fall out.
The hair fall is often in patches on the scalp, but only in extreme cases it can fall out in other places on your body as well. It could include legs and eyebrows.
The stressful event could be a physically traumatic event, a new medication, childbirth, or surgery. It could also be any kind of illness or a stressful life change. The shock of the event generally triggers the change in your hair growth cycle.
Telogen effluvium condition is usually temporary; it does not require treatment. However, you should speak to your dermatologist if you think you have telogen effluvium because they need to rule out other causes.
5 Dandruff or Seborrheic Dermatitis
If you notice ongoing mild inflammation of your scalp, that result in scaly skin is dandruff. Your scalp might be itchy and flake off. Seborrheic dermatitis condition might also affect your ears and face.
Avoid Sun Damage to Your Hair
As your hair is composed of dead protein, it is important to maintain it correctly to optimize its appearance. If you have luxuriantly abundant hair, it is a clue to general good health.
Because your hair does not repair itself, it is susceptible to environmental degradation, especially by dryness, sunlight, chemicals, and physical trauma.
In order to improve and promote healthy-appearing hair, you need to avoid chemical treatments, have an excellent haircut, use hats often, and avoid conditions post-shampoo.
Along with appropriate sleep and exercise, a well-rounded diet will produce a healthy body. This will be manifested in beautiful hair. Poorly conceived dieting and protein restriction might diminish and damage your hair growth.
The Bottom Line
You must be knowing that your hair follicles are responsible for growing hair. You4 hair growth happens in cycles of three distinct phases. These hair follicles also determine your hair color and type.
When damaged, these hair follicles can stop producing hair. As a result, your hair growth cycle can slow down. If you have any concerns regarding your hair growth, talk to your dermatologist.