Causes of Hair Loss

Androgenic alopecia, commonly known as male pattern baldness (MPB), is the primary cause of hair loss in men, and it can be triggered anytime after puberty due to the genetic susceptibility to the effects of Dihydrotestosterone (DHT) which varies widely. While there can be various reasons for hair loss, such as serious illness, reaction to medications, or exceptionally stressful events, heredity is often to blame for most cases of hair loss in men. Despite the myth that baldness is solely inherited from the mother’s father, the reality is that the genetic component of MPB is not fully understood and is believed to be polygenic, involving multiple genes.


Humans have 23 pairs of chromosomes that carry their genetic information, including traits like eye color and toe length. Among these pairs, the “X” and “Y” chromosomes determine biological sex, with women having two “X” chromosomes and men having one “X” and one “Y” chromosome. The gene associated with baldness, called the AR gene, is found on the “X” chromosome. A study of 12,806 men of European ancestry revealed that those with the AR gene had more than twice the risk of developing MPB compared to those without it.

However, the AR gene is not the sole determinant of baldness. Further research in a 2017 review identified 63 genes that may play a role in male pattern baldness, with only six of them found on the “X” chromosome. Additionally, studies have shown that more than 80 percent of individuals experiencing noticeable balding had a father who also experienced hair loss.

A Closer Look at DHT

Dihydrotestosterone (DHT) is a by-product of testosterone, formed through the action of the enzyme Type I and II 5-alpha-reductase, which is present in the oil glands of the hair follicles. While the genetic process of male pattern baldness is now better understood, scientists have known for over three decades that DHT plays a key role in shrinking hair follicles through a process known as miniaturization.

Miniaturization is a biological process driven by hormones that results in the shrinking of hair follicles over time, eventually leading to a bald scalp. The hair follicle growth cycle consists of three phases: the growth phase (anagen), the transitional phase (catagen), and the resting phase (telogen). In hair follicles that are genetically susceptible, the hormone dihydrotestosterone (DHT) can cause the growth phase of the hair cycle to become progressively shorter. As a result, the individual hairs produced by these follicles are unable to reach their full size due to the shortened growth window. Over time, these hairs decrease in size, including both diameter and length, until they eventually disappear. This process of miniaturization is the primary mechanism underlying androgenetic alopecia, also known as genetic hair loss /Male Pattern Baldness.

However, with proper intervention, the miniaturization process can be slowed down or even stopped if detected early enough. Today, there are interventions available that can help in managing the effects of DHT on hair follicles and potentially prevent further hair loss. Early detection and intervention can be crucial in managing the impact of DHT on hair follicles and maintaining healthy hair growth.

Additional Causes of Hair Loss

Androgenetic Alopecia

Androgenetic alopecia, commonly known as male or female pattern baldness, is the most prevalent form of hair loss affecting both genders. This condition is characterized by a progressive thinning...


Certain hair loss conditions are known as "effluviums," a term denoting an outflow. Effluviums specifically impact various phases of the hair growth cycle. Hair follicles on the scalp don't maintain a continuous production of...

Alopecia Areata

Alopecia areata (AA) ranks as the third most common form of hair loss seen by dermatologists, following androgenetic alopecia and telogen effluvium. The lifetime risk of developing AA is nearly 2%, meaning that approximately...

Scarring Alopecia (Cicatricial Alopecia)

Scarring alopecia, also known as cicatricial alopecia, refers to a group of hair loss disorders that may affect up to 3% of individuals experiencing hair loss. It occurs worldwide, impacting otherwise healthy men and women of all ages...

Congenital Hypotrichosis

Hypotrichosis is a term dermatologists use to describe a condition of no hair growth. Unlike alopecia, which describes hair loss where there was formerly hair growth, hypotrichosis describes a situation where there wasn't any...

Hair Shaft Defects

There are numerous conditions in which physical damage to the hair fiber results in hair loss. Sometimes this damage occurs due to improper hair formation by the hair follicles...

Infectious Agents

Ringworm has nothing to do with worms; it is actually a fungal infection. Ringworm is primarily an infectious skin condition that can occur anywhere on the body. If it develops on the scalp, it can cause patches of hair loss...


Over the last three decades, there have been significant advancements in medical treatments for men’s hair loss. The introduction of 5-alpha-reductase inhibitors, such as Propecia (Finasteride), available in oral or topical forms, along with emerging evidence supporting the benefits of low-dose oral minoxidil, has revolutionized the approach to treatment. Furthermore, advancements in surgical hair restoration techniques and regenerative therapies have significantly transformed the landscape. For many individuals, the inevitability of living with noticeable hair loss is no longer a given.

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