A growing number of hair loss studies are focusing on hair follicles and dormancy, a phenomenon in which the follicle enters into a resting phase and never reemerges. This dormancy is one of several factors that may contribute to hair loss, a condition that affects nearly 2 in 3 men and more than 20 million women in the United States alone. Once dormant, hair follicles cease to produce hair. Hair loss becomes visible as larger and more widespread groups of follicles fall into dormancy, often in a predictable pattern that begins along the hairline and extends backward toward the crown of the head (thus the term, “pattern baldness”).