Hair Loss: Causes, Treatments, and Prevention 2025 Guide Hair loss affects millions worldwide. According to the American Academy of Dermatology, about 80 million people in the United States experience hereditary hair loss. The condition, medically known as alopecia, has multiple causes including hormonal imbalance, nutritional deficiency, stress, and genetics. Understanding its causes, treatments, and prevention strategies helps reduce further hair thinning and stimulate natural regrowth. Main Causes of Hair Loss 1. Hormonal Imbalance and Genetics Hormonal imbalance is a leading cause of hair loss in both men and women. The hormone dihydrotestosterone (DHT) , derived from testosterone, shrinks hair follicles and shortens the growth phase. High DHT levels cause androgenetic alopecia , also called male or female pattern baldness. In females, the hormone androgen plays a similar role. Research by the National Institutes of Health confirms that excess androgen levels in women le...