In androgenetic alopecia, what happens to the anagen phase?

• A. Shortened anagen phase
• B. Prolonged telogen phase
• C. Increased melanocyte activity
• D. Increased hair diameter

Answer: (A)

In androgenetic alopecia the key change is in the length of the growth phase of the hair cycle. The follicles that are sensitive to androgens respond to DHT by shortening the anagen (growth) phase. Because each cycle ends sooner, hairs spend less time actively growing, so they become shorter and finer with each cycle. Over time this leads to progressive miniaturization of the follicle and a shift from terminal hairs to thinner, vellus-like hairs.

The other options don’t fit the main mechanism. Prolonged telogen would mean a longer resting phase, which isn’t the defining feature here. Increased melanocyte activity isn’t the driver of the hair‑loss pattern, and increased hair diameter contradicts the observed thinning from miniaturization.