Normally, the hair root is active for up to eight years (growth phase), followed by a resting phase. The hair root releases the hair and it falls out without the threat of hair loss. Subsequently, the hair root starts another growth phase and does so about 14 times before dying.

The testosterone surplus, which begins during puberty, makes beard hair grow on the one hand but also weakens predisposed hair roots in the scalp. Based on the hereditary disposition, the hair roots react supersensitively to testosterone (DHT). It cuts the energy supply, thereby weakening the hair roots. Their growth phases are shortened and their lifetime ends prematurely.

With the corresponding genetic predisposition, testosterone (DHT) prevents the generation of c-AMP, a messenger compound for energy, which is required for the hair roots' metabolism. This shortens growth phases and the hair roots' lifetime ends prematurely. If more and more hair roots die this way, male baldness will be the result.