Final answer:
Hair becomes thinner as we age, predominantly due to changes in the hair growth cycle, hormonal influences, and a decrease in melanin production.
Step-by-step explanation:
As we age, what tends to happen to our hair? The correct answer is it becomes thinner. This is due to several factors, including changes in the hair growth cycle. Hair grows and is eventually shed and replaced by new hair, which occurs in three phases: anagen, catagen, and telogen. During the anagen phase, hair grows actively, whereas the telogen phase is a resting phase. As we age, the anagen phase can shorten, leading to hair growing for a lesser period before it transitions to the resting phase. Therefore, you might not replace hair as quickly as it sheds, and hair density can decrease.
Hormonal and dietary changes can also influence hair loss. Furthermore, the decrease in melanin production, due to aging, leads to gray or white hair. Thinning hair is a common sign of aging and results partly from follicles producing less melanin and the impact of hormones on the hair growth cycle.