One of the most common causes is androgenetic alopecia, often referred to as male-pattern baldness or female-pattern baldness. It's a hereditary condition that affects men and women and leads to a predictable pattern of hair loss.

Various medical conditions and hormonal changes can trigger hair loss. Conditions such as pregnancy, childbirth, menopause, and thyroid problems can lead to significant hair shedding. Moreover, medical conditions like alopecia areata (an autoimmune disorder that attacks hair follicles), scalp infections like ringworm, and diseases such as lupus can cause hair loss.

Certain medications used to treat cancer, arthritis, depression, heart problems, gout, and high blood pressure may have side effects that include hair loss. Chemotherapy and radiation therapy to the head or neck can cause sudden hair loss that typically occurs uniformly across the scalp.