Male pattern baldness is often invisible until you have lost more than 50% of your hair density.

Androgenetic alopecia, commonly known as male pattern baldness, is driven by a sensitivity to dihydrotestosterone (DHT). This hormone binds to receptors in scalp follicles, causing them to shrink in a process called follicular miniaturization. Research published in the Journal of the American Academy of Dermatology indicates that the human eye cannot easily detect a decrease in hair volume until density drops by 50% or more.Each follicle typically goes through a growth cycle consisting of the anagen (growth), catagen (transition), and telogen (resting) phases. When DHT interferes, the anagen phase shortens while the telogen phase lengthens. This results in the hair becoming progressively finer and shorter until the follicle eventually stops producing visible hair entirely. This gradual transition is why many men do not realize they are losing hair for several years.A standard healthy scalp contains approximately 80,000 to 120,000 hairs with a density of about 200 to 300 hairs per square centimeter. Clinical studies using phototrichograms show that visible thinning only becomes apparent when density falls below 110 hairs per square centimeter. This threshold explains why early intervention is critical, as significant damage occurs before the symptoms are physically obvious.The Norwood Scale, developed by Dr. James Hamilton in the 1950s and later revised by Dr. O'Tar Norwood, is the primary classification system used to track these stages. It highlights that by the time a patient reaches Stage 3, they have already experienced substantial permanent loss. Modern treatments like Minoxidil and Finasteride are most effective when started before this 50% visibility threshold is reached.