The Hamilton-Norwood scale is the widely used, reproducible system for classifying the stage of male pattern hair loss. It ranges from 1 to 7, with an "A" variant describing cases where recession progresses primarily along the front hairline.
| Stage | Description |
|---|---|
| Type 1 | No significant loss or minimal temple recession |
| Type 2 | Mild, symmetrical temple recession |
| Type 3 | First clinically significant stage; deeper temple recession |
| Type 3 Vertex | Noticeable thinning begins at the crown (vertex) |
| Type 4 | A band of moderate-density hair still separates the front and crown |
| Type 5 | The separating band narrows as the two bald areas move closer |
| Type 6 | The front and crown areas merge |
| Type 7 | Most advanced stage; only a narrow band remains at the back and sides |
Why it matters: The stage is a core reference point both for surgical planning (grafts required, donor area sufficiency) and for anticipating future loss risk.