This is because the hair in this so-called Hippocratic crown has no testosterone receptors. It is this hormone that is involved in hair loss during successive growth and fall cycles.
These cycles, of which there are around twenty, vary from three to seven years. For some, they are shortened (sometimes to one year) due to a genetic propensity to baldness and the action of testosterone.
The distribution of hormone receptors is established when the fetal skull is formed. Women are not affected, as they produce less testosterone.
There is no official name for this appearance, but the terms “U-shaped” or “horseshoe” hairline are often used.
However, if the temples are only receding and have not yet disappeared, the term “M-shaped demarcation line” may be more appropriate, due to the pointed appearance at the front.
The term “horseshoe-shaped hairline” refers to the appearance of the hairline as seen from above in the more advanced stages of baldness.
