What Is Hair Loss ?

Hair loss is a common condition which is cosmetically and psychosocially distressing. It is an ever growing problem affecting about 58% of the indian population, androgenic alopecia (AGA) being the most common cause. As has the population who suffer from hair loss grown statistically, so have the options for their management. The sudden spurt in treatment/management options are majorly driven by marketing compulsion and fewer by scientific evidences. These prey on those who may be concerned about recent or dramatic hair loss. It’s always advisable to exercise caution when considering these products. Always be suspicious of treatments that offer a large benefit for very little in return. It’s always better to trust people who have maintained a high scientific temperament, been into healthcare business for long, have strong brand equity to defend and are trusted into all their fields of operations.

What is hair?

Hair is a protein filament that grows from follicles found in the dermis layer of skin. It is a collective term for slender, threadlike outgrowths off the epidermis of mammals, forming a characteristic body covering.

The word "hair" usually refers to two distinct structures: Hair Follicle & Hair Shaftc

Hair Follicle:

A hair follicle anchors each hair into the dermis. The hair bulb forms the base of the hair follicle. It maintains stem cells, which re-grow the hair after it falls out.

Hair Shaft:

In the hair bulb, living cells divide and grow to build the hair shaft. The shaft is the hard filamentous part that extends above the skin surface. A cross section of the hair shaft may be divided roughly into three zones:

  • Cuticle which consists of several layers of flat, thin cells laid out overlapping one another as roof shingles.
  • Cortex which contains the keratin bundles in cell structures which are roughly rod-like.
  • Medulla is a disorganized and open area at the center of the fiber which contains pigment for hair colour.
What are different types of hair?

Basis the follicle size, hair can be classified into three major groups.

Lanugo:

It’s the first hair to be produced by the fetal hair follicles, and it usually appears on the fetus at about 5 months of gestation. It’s very fine, soft, and usually un-pigmented. Lanugo is normally shed before birth, but sometimes maybe present at birth.

Vellous:

It’s short, fine, light-colored, and barely noticeable thin hair that develops on most of a person's body during childhood except, lips, ear, palm, sole, navel etc. Vellous hair is most easily observed on children and adult women, as they generally have less terminal hair to obscure it. Vellous hair is not lanugo hair. Lanugo hair is a much thicker type of hair that normally grows only on fetuses.

Terminal:

Terminal hairs are thick, strong, pigmented hairs that have fully matured. These hairs can be found in abundance on the scalp, in the pubic region, under the arms, and on the face (males only). During puberty, the increase in androgenic hormone levels causes vellus hair to be replaced with terminal hair in certain parts of the human body.

What is the normal density of hair on the scalp?

A human head has anywhere between 100,000 and 150,000 hairs. There are multiple factors like age, gender, and ethnicity which affect number, caliber and density of hair. Accurate quantitative analysis of scalp hair density is difficult and time consuming. Apart from the palms and soles almost all skin has follicles. But not all hair grows to the same length or at the same rate.

How does hair grow?

Hair grows out of follicles. In simple terms:

  • Hair begins growing from root in the bottom of the follicle which is made up of keratinocytes which synthesize a protein called keratin which is the main protein of the hair.
  • Blood from the blood vessels in the scalp feeds the root, which creates more cells and makes the hair grow.
  • The hair gets pushed up through the skin as it grows, passing an oil gland along the way. The oil gland adds oil to the hair and keeps it shiny and soft. It can make it greasy, too.
  • The hair dies by the time it is long enough to poke out through the skin. Yes, hair is dead. That's why it doesn't hurt to get a haircut.

Hair growth occurs in cycles consisting of three phases:

  • Anagen (Growth phase): It’s the active growth phase in which the root of the hair divides rapidly, adding to the hair shaft. Hair stays in this growth phase for 2–7 years & grows about 1 cm every 28 days.
  • Catagen (Transitional phase): The catagen phase is a short transition stage occurring at the end of the anagen phase. It signals the end of the active growth of a hair & lasts for about 2–3 weeks.
  • Telogen (Resting phase): The telogen phase is the resting phase of the hair follicle. When the body is subjected to extreme stress, as much as 70 percent of hair can prematurely enter a phase of rest, called the telogen phase.
Why does the length of hair vary so much?

If the hair is not trimmed, it can be grown quite long, but there is an upper limit to the maximum length that scalp hair can grow to.

Multiple papers examine the time duration for which scalp hair follicles actively produce a hair fiber. The most frequently quoted time period is 1000 days (2-6 YEARS), but this figure is a rough approximation. The time duration of anagen growth, plus knowing what length of hair fiber a scalp hair follicle can produce per day, will enable a calculation of the average maximum length that scalp hair can grow to. Research on humans suggests that active hair fiber growth production from scalp hair follicles may last from 500 to 1800 days. The scalp hair fiber growth rate is between 0.3 to 0.4 mm a day. For the most part, the studies were done with male volunteers, but a few other studies indicate similar results for women too. Put together in a calculation, the research would suggest that the maximum length scalp hair can grow to, is between 20 and 60 centimeters. However, it is quite often seen that some people are able to grow their hair much longer. The upper limit to scalp hair length is determined by our genes. Some people have genes for short hair, others grow hair much longer.

How is the hair growth regulated?

It’s the game of hormones like androgens which are important control factors in hair growth and in inherited pattern hair loss. Key control factors are Testosterone (Androgen) and its metabolite dihydrotestosterone (DHT).

  • Testosterone majorly acts as a key control factor in the growth of beard, underarm and pubic hair.
  • Scalp hair loss is associated with presence of DHT in male and female pattern hair loss. DHT plus the presence and activity of hair loss gene(s) are the key factors underlying male and female pattern hair loss. The androgens mediate their effect by binding to the androgen receptors present in the follicle. The testosterone is converted to DHT by the action of the enzyme 5-Alpha reductase. The DHT then binds to the receptor and initiates its action.

Hair loss is a common condition which is cosmetically and psychosocially distressing. It is an ever growing problem affecting about 58% of the indian population, androgenic alopecia (AGA) being the most common cause. As has the population who suffer from hair loss grown statistically, so have the options for their management. The sudden spurt in treatment/management options are majorly driven by marketing compulsion and fewer by scientific evidences. These prey on those who may be concerned about recent or dramatic hair loss. It’s always advisable to exercise caution when considering these products. Always be suspicious of treatments that offer a large benefit for very little in return. It’s always better to trust people who have maintained a high scientific temperament, been into healthcare business for long, have strong brand equity to defend and are trusted into all their fields of operations.