Hair Loss in Men

Androgenetic Alopecia, commonly referred to as “male pattern baldness” is caused by a combination of genetics and hormones called androgens. This condition affects approximately 40 million men in North America.

What Causes Male Pattern Baldness?

People are born with a finite number of hair follicles. The density, diameter and colour of hair follicles change with age, however, the quantity does not increase. Genetically-controlled hair loss in men is called Androgenetic Alopecia, but is often referred to as “Male Pattern Baldness” due to the distinct patterns in which it occurs.

Male pattern baldness is caused by the effect of dihydrotestosterone (DHT), a by-product of the male hormone testosterone, on sensitive hair follicles. Men with androgenetic alopecia have receptors on hair follicles which are sensitive to DHT. The presence of the DHT receptors is genetically predetermined. DHT binds with these receptors causing the hair follicle to decrease the length of time it stays in the hair growth or “anagen” phase and lengthen its resting or “telogen” phase. With passing phases of growth, the hair shaft becomes smaller and shorter (miniaturization) until eventually there is no growth. This results in thinning and eventually baldness.

Phases of Male Pattern Baldness

There is a normal maturation of the hair growth pattern in all men by their early 20’s, often detectable by some recession of the hairline in the forehead and temple region. Male Pattern Baldness, which affects many men from the age of 20 onwards, however, is characterized by a more significant progression of hair loss in the forehead, temples and occasionally in the crown region. Initially noticed as excessive hair loss in the shower or on the pillow, men eventually begin to see thinning in these regions. Hair loss actually begins long before it is noticeable; approximately 50 percent of the hairs in a given area are often lost before noticeable thinning becomes apparent. As hair loss progresses, men often seek treatment to reverse or minimize ongoing hair loss and restore the loss that has occurred.

Hair Loss in Men working file copyThe Norwood Classification of Hair Loss

The distinct patterns that characterize men suffering from Androgenetic Alopecia have been detailed in The Norwood Classification of hair loss which is illustrated below.

The Role of Genetics and Hormones

There are several variables that are responsible for causing male pattern baldness, including genes, hormones and age. Genetics are a necessary component of hair loss and can be passed on by either parent. This genetic transfer is not predictable and may skip a generation, or affect only a sibling or two in the family. The common belief that baldness is genetically transferred only from the mother’s side of the family is incorrect. The genetics of male pattern baldness is complicated and not completely understood but is believed to involve more than one gene.

The presence of the hair loss gene is not enough for baldness to occur, as other variables such as hormones and age also play a role. Hair loss may begin any time after puberty as testosterone levels begin to rise. The first change is usually recession in the temporal areas, which is seen in almost all mature Caucasian males, including men whose hair loss will not progress beyond the temporal regions. This type of recession, that does not progress is a normal physiologic change and does not require management or treatment. Hair loss that continues should be addressed as soon as possible.

The Role of DHT

When testosterone is chemically altered by the enzyme 5-alpha reductase in the skin, it becomes a more potent hormone, known as dihydrotestosterone (or DHT). DHT affects hair loss by binding to special receptor sites on the cells of the hair follicles. The effect is not immediate, however, and susceptible hair follicles must continually be exposed to DHT over a period of time for hair loss to occur.

‘Miniaturization’ of Hair Follicles

Once the effect of DHT begins to manifest itself, the length of the anagen (growing) cycle of the hair decreases and the telogen (resting) phase of the hair lengthens. Genetically susceptible hair follicles that were producing healthy hairs will begin to produce thinner, shorter, more brittle hairs with weaker shafts (“miniaturization”). As the condition persists, the follicles become finer until they become almost invisible, short, vellus hairs, or die out altogether.

Accelerated hair loss does not occur at a consistent rate or all at once, but rather in waves. People who are losing their hair experience alternating periods of slow and rapid hair loss as well as periods of relative stability. Many of the factors that cause the rate of hair loss to accelerate or decelerate are unknown.

Am I a Candidate for Male Hair Restoration?

You may be an ideal candidate for male hair restoration if:


  • You are suffering from Androgenetic Alopecia.
  • You are experiencing hair loss due to trauma (including burns or incisions from surgical procedures).
  • You wish to improve your hairline.
  • You wish to have fuller eyebrows
  • You are experiencing traction or marginal alopecia.