Hair loss causes in men are 95% of the time dependant on the action of male hormones (androgens) on receptive hair follicles; called androgenetic alopecia. Androgenetic alopecia is the scientific name for the genetic predisposition for male pattern baldness or male pattern hair loss.
Please note; causes of hair loss do not include blocked hair follicles, build-up of androgens, scalp oils, poor circulation, inadequate oxygen, constant stress, or inadequate nutrition.
For hair loss due to androgenetic alopecia to occur, there must be;
- A genetic propensity for balding.
- The presence of androgens, or male hormones.
- Enough aging time to allow the first two factors to exert their influence on the hair follicles.
Are Hair Loss Causes Unavoidable?
Male pattern hair loss causes occur in predictable stages and is progressive. Those with male pattern hair loss will, if they live long enough, eventually progress from the early stages of hair loss to the advanced stages. Male pattern hair loss starts with the hairline or back of the head, advances to thin the top of the head, and often leaves just a fringe of hair extending from ear to ear across the back of the head. In extreme cases, even this fringe is lost eventually.
These causes of hair loss result from inheriting genes for hair loss. The genetic traits for male pattern baldness can come from either parent. Inheriting these genetic hair loss causes of hair loss will mean that certain cells in certain hair follicles will be receptive to hormone messages, and after receiving the message, those cells cause the follicle to begin to grow less hair.
Role of Androgens, 5-Alpha Reductase, and DHT Dihydrotestosterone in Causes of Hair Loss
Hair loss causes by hormones that affect hair follicles fall into the broad class of hormones known as androgens. The most common of these hormonal causes of hair loss are testosterone, androsteinedione, and dihydrotestosterone DHT. Testosterone can be converted into DHT dihydrotestosterone, the potent hair loss hormone, by 5-alpha reductase, an enzyme found in skin cells and hair follicles and which is produced in the prostate, adrenal glands, and the scalp.
As blood circulates around hair follicle cells providing oxygen and nourishment, hormones in the blood also communicate messages to the cells. At the hair follicle, testosterone is converted by an enzyme called 5 alpha reductase into another form of testosterone called dihydrotestosterone DHT. In men who are prone to hair loss, certain hair follicles (in the areas that become characteristically bald) tend to produce more of the enzyme 5-alpha reductase which grabs testosterone from the blood and converts it into DHT dihydrotestosterone. DHT is the central factor in hair loss.
Men suffering from hair loss causes have high levels of dihydrotestosterone DHT in their scalp. DHT dihydrotestosterone is the androgen hormone that triggers hair loss in androgenetic alopecia. When hair follicles that are genetically programmed to be receptive to dihydrotestosterone DHT receive the DHT message over a long enough period of time, the follicle begins to produce less hair. In short, 5-alpha reductase levels and DHT dihydrotestosterone together are the key hair loss causes in men.
Men with thin hair may have the same amount of testosterone as those with thick hair. The difference is in their hair follicle’s genetically programmed receptiveness to dihydrotestosterone DHT. Even on the same man’s head, where all the follicles have the same exposure to hormones in the blood, some follicles are programmed to keep growing, while others begin to spend more time resting. Genetic programming is another of the key cause of hair loss in men.
When a man begins to experience pattern hair loss, follicles genetically programmed to spend more time resting begin to develop DHT receptor sites. The DHT dihydrotestosterone attaches itself to these receptor sites and starts to treat the follicle as a foreign object in the body. This can also cause itching, inflammation and oiliness. Under attack from DHT dihydrotestosterone, the follicle begins to miniaturize with every growth cycle, until after several years, it simply becomes too small and short to be seen.
Therefore, male pattern causes of hair loss depend primarily on 5-alpha reductase levels, and consequently DHT levels and its binding effect on genetically predisposed hair follicles.
The Time Factor in Hair Loss Causes : Anagen Phase and Telogen Phase
When the DHT hormone binds to a hormone receptor on the hair follicle, it slows down hair production by causing them to spend less time in the growing stage (anagen phase) and more time in the resting stage (telogen phase) of the hair cycle. The hair follicles then produce a hair thin in diameter, called vellus hair. This is the fine fuzz on the scalps of men who are going bald. These hair loss causes in men occur when the follicles spend less than the normal amount of time in the growing stage because of the influence of DHT dihydrotestosterone. They then tend to produce vellus hair and may eventually stop making scalp hair altogether.
The time period for exposure to DHT dihydrotestosterone is a critical factor in the progression male pattern hair baldness, and it can take many decades for some genetically programmed follicles to get the message to stop producing hairs. Over time, the action of DHT causes the hair follicles to degrade and shortens the anagen phase (growing phase). Some follicles will gradually die, but most will simply shrink to the size they were when you were born and produce weaker hairs.
With a shortening anagen phase and a longer telogen phase more hairs are shed as a result of these hair loss causes, the hairs becoming thinner and thinner until they are too fine to survive daily wear and tear. Telogen phase (resting phase) hairs are easily dislodged during washing, drying, or combing; in addition to thinning and miniaturization of the hairs, we begin to see larger numbers of hairs on the comb, the towel, the pillowcase, or in the bathroom drain.
Balding hair gradually changes from long, thick, coarse, pigmented hair into fine, unpigmented vellus sprouts. The telogen phase is a central process in the causes of hair loss. The sebaceous gland attached to the follicles remain the same size. As the hair shafts become smaller, the gland continues to pump out about the same amount of sebum oil. So as your hair thins, you will notice that your hair becomes flatter and oilier. Sebum can contain a high level of 5-alpha reductase. So most doctors agree that frequent shampooing is advised to avoid hair loss resulting from oily scalps.
At present there is no absolute cure for androgenetic hair loss causes in men. There is nothing that will stop the condition once and for all. There are however, many effective treatments for hair loss, and each has advantages and disadvantages.