Hair loss is a very common issue that affects almost everyone at some stage of their life. It is more frequently seen in males, generally starting from the age of 25 until the age of 50 and it affects approximately 70% of all men at some stage of their lives.
Hereditary hair loss
Androgenetic alopecia in men
Hereditary hair loss is called androgenetic alopecia. This is where the hair follicles are damaged on the scalp. Hair is hypersensitive to the male sex hormone testosterone. Andogenetic alopecia affects the growth phase of the hair. Hereditary hair loss in men is recognised initially by so-called receding hairline and often continues with bald spots on the crown.
History of hereditary hair loss
The first signs of this genetic predisposition appear after puberty between 20 and 30 years. Usually there is thinning hair at the crown. In some men, this can expand all over the head. However, many keep their hair at the temples and at the nape.
The interaction of different factors
In androgenetic alopecia three factors play an important role:
Age of person
If a person has a genetic predisposition to lose hair, this will generally result in slowing the regrowth of hair. In both women and men the production of endogenous growth factors such as IGF-1 (insulin-like growth factor), KGF (keratinocyte growth factor) and VEGF (vascular endothelial growth factor) decreases as they grow older and hair that has fallen out won’t grow back due to lack of growth stimulation.
Hormones affect the length of the hair cycle and the division activity of the hair follicles.
As early as 20 years of age, the production of growth hormone HGH (human growth hormone) decreases. Every ten years this reduces further by 14% and this affects hair regrowth.
The enzyme 5-alpha-reductase
The male sex hormone testosterone is converted by the enzyme 5-alpha-reductase into dihydrotestosterone (DHT). DHT damages and weakens the hair roots. The enzyme 5-alpha-reductase exists in two types:
- as 5-alpha-reductase I (5aR1) in the front part of the scalp
- as 5-alpha-reductase II (5AR2) in the entire scalp
In people with an inherited hypersensitivity to DHT, the phase of hair growth (anagen) is shortened and results in a decrease in the length of hair. A bald man does not fewer hair follicles as a man with full hair growth, but because of the shortened growth phase the hair is barely visible. The scalp at the back and in the neck area is less sensitive to DHT generally.
Hair loss due to unbalanced and inadequate nutrition
Iron, zinc, sulfur and the vitamin B group care for healthy hair.