Final answer:
Androgenetic alopecia leads to the shrinking of scalp follicles, resulting in the shortening of the hair's active growth (anagen) phase and potentially a longer resting (telogen) phase, which causes hair loss.
Step-by-step explanation:
In androgenetic alopecia, a combination of heredity, hormones, and age causes the shrinking or miniaturizing of certain scalp follicles. This condition affects the hair growth cycle by shortening the anagen phase, which is the active phase of hair growth and may prolong the telogen phase, where the hair follicle is at rest. As the miniature follicles produce weaker and thinner hairs, this ultimately leads to noticeable hair loss. Androgenetic alopecia can also be influenced by hormonal changes that occur during life transitions, such as menopause, where there is a decrease in hormonal levels that regulate hair growth.