Getting older is one of the most common causes of hair loss. Nearly everyone has some hair loss with aging as the rate of hair growth also slows. As we age, hormone levels change (consider menopause in women), and hair follicle size also diminishes, contributing to hair loss. In men, hair loss due to aging frequently begins at the temple and crown. In women, it is more widespread across the scalp, but not as noticeable.
Hair strands become smaller and have less pigment. So the thick, coarse hair of a young adult eventually becomes thin, fine, light-colored hair. Plus many hair follicles stop producing new hairs.