What Does the Hamilton-Norwood Scale Tell Us About Hair Loss?

What Hamilton Norwood Scale Explains

The Hamilton-Norwood Scale (HNS) is widely used in clinical practice to evaluate the severity and progression of androgenetic alopecia (AGA).

Hamilton introduced an earlier classification, which Norwood later revised. The commonly used Norwood scale describes types I–VII, with a type III vertex pattern and type A variants. It should not be mixed with Hamilton’s older I–VIII descriptions.

Stages in HNS

Type I: little or no hairline recession.

Type II: mild recession at the temples.

Type III: deeper temple recession; the III vertex pattern also describes crown loss.

Type IV: more extensive frontal and crown loss, separated by a band of hair.

Type V: the frontal and crown areas of loss enlarge, and the separating band becomes narrower.

Type VI: frontal and crown areas of loss merge as the separating band is lost.

Type VII: extensive loss leaves a narrower horseshoe-shaped band around the sides and back.

Insights from a Hair Transplant Surgeon: Understanding Your Hair Loss Stage

The scale describes a pattern; it does not diagnose every cause of hair loss, predict an individual’s future loss or determine a graft count by itself. Planning also considers donor supply, scalp examination and medical history.