Androgenetic alopecia is a condition in which hair loss results in a more or less significant thinning of the top of the scalp. Androgenetic alopecia affects one-third of men by the age of 30 and almost half by the age of 50.

What is androgenetic alopecia?

Androgenetic alopecia is generally hereditary and is the most common cause of baldness in men. The hair located on the frontal area and the vertex becomes thinner, before disappearing completely. On the other hand, a crown of hair remains around the temples and the back of the neck for the rest of the patient’s life.

Homme de dos

What is the cause of androgenetic alopecia in men?

Androgenetic alopecia is the result of two factors:

The presence of testosterone the genetic predisposition of hair follicles to be affected by male hormones Testosterone usually binds to a protein that neutralizes it.

But a fraction can stay biologically active and reach the hair follicles.

Testosterone is then transformed into a new hormone, dihydrotestosterone (DHT), under the effects of an enzyme called 5 alpha-reductase.

If the patient’s hair follicles are genetically programmed to be sensitive to DHT, then DHT will inevitably accelerate the hair growth cycle until the hair renewal capital is depleted early.

DHT also causes an excessive secretion of sebum, which will stagnate in the hair follicle. Under the effect of sebum, the scalp will thicken and prevent the blood vessels from irrigating capillary roots sufficiently.

Proper irrigation is essential for the hair follicles to be replaced effectively. In the long term, the hair will disappear for good if no treatment is implemented.

How to identify androgenetic alopecia in men?

Androgenetic alopecia always progresses in the same way and affects the same areas of the scalp, i.e. the frontal area and the vertex, regardless of the patient.

Dr. Pierre Bouhanna established a five-stage clinical classification to evaluate the severity of baldness:

  • Stage 1a: The hairline recedes in the forehead area.
  • Stage 1b: A crown begins to appear at the top of the skull.
  • Stage 2a: The hairline gradually recedes to the top of the skull.
  • Stage 2b: Frontal and vertex thinning.
  • Stage 3: The thinning reaches the top of the skull, a hairy crown is maintained around the temples and the back of the neck. Baldness is now considered “complete”.

Note that not all androgenetic alopecia progress the same way. It will depend on genetic and environmental factors and whether a specific treatment has already been introduced. Only a thorough hair diagnosis will allow us to precisely determine your alopecia’s progress.

Classification Norwood Hamilton pour l'alopécie androgénétique masculine