There are actually two different types of hair loss. The first is called shedding, and is a healthy part of our hair’s growth cycle - hairs with diameters of normal size fall out in a diffuse fashion around the head, and, after a rest period, a new normal hair grows in its place, says Bernard Cohen, MD, a certified dermatologist and hair restoration surgeon in. Coral Gables, Fla.

In contrast, the problematic type of hair loss is called, plainly, balding. One form of balding, called telogen effluvium, is basically just excessive shedding brought on by unusual circumstance or trauma, such as chemotherapy, high fever, pregnancy, drugs, anemia or even stress. These instances are generally temporary, and each hair lost will eventually be replaced with a full-sized hair. But the other, more common type of balding which we all know and don’t exactly love, is actually properly referred to as androgenetic alopecia, or thinning.

“With thinning, the number of hairs stays the same, but each time they re-grow, they have a smaller diameter and length until eventually they vanish - this process is called miniaturization,” Cohen says. “The underlying skin becomes more and more visible as the hairs become smaller and smaller, however, a person will already have lost 50 percent of their hair before it is even noticeable.”