What is androgenetic alopecia?

What role do genes and hormones play in constitutional hair loss (AGA)?

Androgenetic alopecia

Androgenetic alopecia (AGA for short) is the most common form of hair loss. In men, this variant accounts for 80 percent of all hair loss1. So, what is androgenetic alopecia? The meaning is already in the name and can be freely translated as "hair loss caused by male sex hormones". However, not only hormones, but also a genetic predisposition and external factors play a role in the causes of constitutional hair loss.

In this article you will learn why not only men but also women can be affected by the so-called male pattern hair loss. You will also find information about the influence of hormones, genetic predisposition and external factors such as stress or age on the development of androgenetic alopecia.

In addition, you will receive tips on how to recognize predisposition-related hair loss in yourself and what options exist for treatment and prevention - because predisposition-related hair loss is not a fate that you have to surrender to!

  1. Androgenetic alopecia in men and women
  2. Influence of hormones
  3. Influence of genetic predisposition
  4. Influence of external factors
  5. Course of androgenetic alopecia
  6. Treatment of constitutional hair loss

Androgenetic alopecia in men and women

The term "androgenetic alopecia" is composed as follows:

  • Androgenetic means as much as "caused by male sex hormones". This is because male sex hormones are referred to as androgens in medicine. They play a particularly important role in this form of hair loss.
  • Alopecia is an umbrella term for various forms of hair loss.

The best-known androgen is testosterone. Although it is considered a male sex hormone, it is also produced in the body of women. In the case of constitutional hair loss, there is an inherited hypersensitivity to a degradation product of testosterone: dihydrotestosterone, or DHT for short.

Therefore, androgenetic alopecia can affect both men and women. However, this form of hair loss usually differs in progression and severity between the sexes.

There are a number of other names for androgenetic hair loss:

  1. Alopecia androgenetica
  2. AGA
  3. androgenic hair loss
  4. androgenic alopecia
  5. constitutional hair loss
  6. hereditary hair loss
  7. genetic hair loss
  8. male pattern hair loss

Influence of hormones

Hair loss hormones

Hormones regulate countless bodily functions, including the length of the growth phase of your hair. Dihydrotestosterone is found in every organism and is not a problem for a full head of hair in the first place. In addition, the hormone has an influence on a number of other functions, including2:

  • Formation of male sex organs
  • Beard growth
  • Body hair
  • Sebaceous glands

DHT is formed from testosterone by the enzyme 5-alpha-reductase. This means that it is not testosterone that is actually the effective hormone, but dihydrotestosterone. But if DHT influences beard growth and body hair in men, how can it be responsible for androgenic hair loss at the same time?


Hair roots hypersensitive to DHT

DHT actually has a seemingly paradoxical effect in this respect. On the one hand it promotes body hair, on the other hand it can cause head hair to fall out3. The peculiarity of androgenetic alopecia is that those affected react much more sensitively to the DHT present due to genetic predisposition.

This leads to the following effects on the head hair:

  • The hair follicles (the structure surrounding the hair root) can shrink
  • The follicle is less well supplied with blood and nutrients and oxygen
  • The growth phase of the hair is shortened - normally it lasts two to six years
  • The hairs atrophy, become thin and light in color and fuzz develops (so-called vellus hairs)5
  • In a final step, the hair roots can die completely

Influence of genes

Hair loss genes

Dihydrotestosterone is directly responsible for hair loss in androgenetic alopecia. But it is the inherited hypersensitivity to DHT that determines whether the hair falls out prematurely and the head becomes bald. Surely you have already observed this yourself in your immediate environment:

  • There are older people who still have a full head of hair. At most, the first receding hairline forms on the forehead beyond the age of 70.
  • And then there are the 20- to 30-year-olds, for whom the hair on their heads begins to thin just a few years after leaving school. In men in particular, baldness can occur frequently from the age of thirty.

Details about inheritance are still partly unclear, but the following things are certain:

  • Men from families with androgenetic alopecia are more often affected than women
  • Only 20 percent of those affected have no other cases in the family
  • Women can also inherit the condition-related hair loss6

However, it is also possible that you are a carrier of the gene mutation, but still do not develop androgenetic alopecia.


Inherited hypersensitivity of the hair roots

Sensitivity to DHT does not seem to be triggered by a single hereditary disposition. Probably only the combination of different hereditary factors, which are passed on via the father or the mother, determines whether or not hereditary hair loss occurs.

The hereditary factors can influence the hypersensitivity in two ways7:

  1. Increased number of DHT receptors on the hair follicles, which allows the hormone to bind better and thus act.
  2. Greater amounts of the enzyme 5-alpha-reductase, resulting in more testosterone being converted to dihydrotestosterone.

Each person is unique in the combination of hereditary traits that are responsible for their hair growth. For both men and women, it is impossible to predict with certainty who will be affected by androgenetic alopecia, at what age hair loss will begin, and how severe or fast it will progress.

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Influence of other factors

In addition, there are external factors that also influence the intensity and the course of the constitutional hair loss. The intensity can be increased, for example, by:

  • Persistent stress: If the body releases increased stress hormones, this can lead to a lack of energy in the hair roots. Plant-related hair loss is accelerated in this way.
  • Certain seasons: Some people experience an increase in hair loss in spring and/or autumn, for example.
  • Incorrect diet: An unbalanced diet can also affect hair growth. If the follicles are not supplied enough with nutrients such as vitamins and proteins, deficiency symptoms can occur. The hair becomes brittle and dull and can fall out.

For more information on the effects of chronic stress on hair, read the article Hair loss due to stress.

More hair loss with age

In general, it is the combination of age and genes that is largely responsible for the development of androgenetic alopecia. This is because the intensity and frequency of this hair loss increases with age. The only difference is when and how quickly the genetic influence becomes noticeable. For some it is earlier, for others later.

By the age of 60, around 80 percent of all men and 60 percent of all women of European origin are affected to a greater or lesser extent by hereditary hair loss8.

Even if you do not have a hereditary predisposition, hair loss usually increases with age. In the case of androgenic hair loss, on the other hand, this can occur much earlier and, above all, faster.

Course of androgenetic alopecia: hair loss at 20

In extreme cases, androgenetic alopecia begins shortly after puberty on entering adulthood. More frequently, however, hair loss begins between the ages of 20 and 30. From the age of 40, androgenetic alopecia usually shows its full expression.

Androgenic hair loss usually begins with receding hairline

In men, alopecia androgenetica usually follows the following course9:

  • It starts with a slight hair loss on the forehead and temples, so-called receding hairline appears
  • The forehead-hair boundary (hairline) recedes further, the hair loss expands to a bald forehead
  • The hair on the entire head becomes thinner and bald patches are formed
  • These bald patches unite to form a so-called tonsure, a larger hairless region in the middle of the head
  • In the further course of the disease, the hair becomes mostly bald, only on the lower back of the head and on the sides of the head the hair is usually preserved (crown of hair)

The different stages of androgenetic hair loss according to the male course are summarized in the Hamilton-Norwood scale.

Hamilton-Norwood scheme Androgenetic alopecia

Different course in women

In women, congenital hair loss proceeds somewhat differently. The typical male sign, receding hairline, occurs only extremely rarely. Typically, hair loss in the female sex begins at the parting. The hair becomes thinner and then falls out more. Starting from hair parting, an increasingly larger, very thinning area is formed.

Although the first signs of androgenic hair loss can also occur in women as early as adolescence, it often worsens during menopause. Scientists attribute this to the increased influence of male sex hormones on the woman's body that then sets in, and at the same time the influence of estrogens wanes.

Nevertheless, there are indications that 5-alpha-reductase and DHT play a lesser role in female androgenic alopecia than in men10.

Treatment of constitutional hair loss

Treatment androgenetic alopecia

The earlier the hereditary predisposition to hair loss is recognized, the better those affected can prevent the progression of hair loss and preserve the existing hair. Once hair roots and follicles have atrophied and died, this can no longer be reversed.

If you notice the first signs such as increased hair loss, a decrease in the hairline on the forehead or receding hairline, you can already effectively counteract the hair loss with a suitable caffeine hair care.

In the case of severe hair loss, it is also advisable to go to the doctor. The first point of contact is usually the family doctor or dermatologist. After taking a medical history, he or she will be able to make a diagnosis and initiate suitable treatment. This consists, for example, of:

  • The use of shampoos or liquids containing caffeine
  • Taking certain medications, such as finasteride
  • Laser therapy against hair loss
  • Hair transplantation as a last resort

Here you will find more information about the advantages and disadvantages of the various
hair loss remedies

Caffeine: Growth engine for the hair roots

Many people know caffeine mainly in the form of fragrant coffee or as a refreshing stimulant in cola. But caffeine - applied topically in the right concentration - also gives hair roots new strength and is a particularly well-studied compound in hair care for hair loss.

In various scientific studies, caffeine has been found to support hair growth and, accordingly, to be of great importance in the treatment of androgenetic hair loss11. Local application on the head, e.g. as ashampoo or liquid, is associated with many benefits for the hair. For example, caffeine strengthens hair and promotes its growth directly in the roots12.

Moreover, it has been found that local caffeine hair care leads to equivalent results as the application of the medical hair restorer minoxidil13.

Caffeine hair care from Alpecin

With many decades of experience in researching hair loss and scalp problems, Alpecin offers various hair care products that are in line with the latest scientific findings on the treatment of AGA.

In 2004, Alpecin achieved a breakthrough in research: caffeine helps counteract the negative influence of DHT at the hair root. The proven caffeine shampoo C1 is developed and strikes a chord with men. A good 10 years later, the 100 millionth bottle of Caffeine Shampoo is sold. Today, Alpecin products are available on all continents and in more than 50 countries.

In addition, other caffeine products have been developed that specifically target various scalp problems while taking advantage of the positive effects of caffeine:

  • The Double Effect Caffeine Shampoo counteracts the two most common hair problems affecting men: hereditary hair loss and dandruff associated with an oily scalp
  • The Hybrid Sensitive Caffeine Shampoo relies on a moisturizing effect in addition to the proven caffeine complex: dry scalps are gently soothed and scalp itching is reduced
  • The Tuning Shampoos prevent androgenic hair loss and darken the natural hair color and the first gray hairs with a color effect
  • The Caffeine liquid supplies the hair roots with caffeine even on days without hair washing

These caffeine hair care products should be used daily for an optimal effect. A constitutional hair loss is in no way a fate to which one must surrender. Often it can be effectively counteracted with the right hair care.


Suitable products against androgenetic alopecia

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