Fundamentals

The Norwood scale, honestly

Clinicians don't say "thinning a bit." They use a seven-stage map — and knowing where you sit on it changes what the evidence can tell you.

By the Editorial Team · Citations below · Medical review: pending — treat as education, not advice

Where the scale comes from

James Hamilton proposed the first systematic classification of male pattern baldness in 1951, observing patterns across more than 300 men. O'Tar Norwood revised and extended it in 1975 into the seven-stage system (with variants) that dermatology still uses today. It isn't a severity score of how you look — it's a map of which zones are affected: the frontotemporal hairline, the crown (vertex), and eventually the bridge between them.

The seven stages, in plain language

• N1 — adolescent or juvenile hairline, no visible recession.
• N2 — slight, usually symmetrical recession at the temples. Common and often stable for years.
• N3 — the first stage Norwood classified as balding: deeper temple recession; the "3 vertex" variant adds crown thinning.
• N4 — further frontal recession plus an enlarging crown area, still separated by a band of hair.
• N5 — the separating band thins; front and crown begin to read as one area.
• N6 — the bridge is gone; frontal and crown regions have merged.
• N7 — the horseshoe: hair remains only on the sides and back, the zones most resistant to androgen-driven loss.

Why stage changes the conversation

Almost every treatment trial enrolls and reports by pattern and stage. The pivotal finasteride trials, for instance, enrolled men with predominantly mild-to-moderate vertex loss; the minoxidil comparison trials similarly studied defined stages. Extrapolating those results to an N6 pattern isn't supported by the same evidence — which is one reason "it worked for him" is a weak basis for expectations.

Self-assessing without fooling yourself

Two honest problems: you can't see your own crown, and day-to-day variation (lighting, haircut, wet vs. dry) swamps slow change. What works better:

1. Photograph hairline and crown monthly, same angle, flat indoor light.
2. Compare across quarters, not days.
3. If it matters for a treatment decision, get a dermatologist's staging — a trained eye with a dermatoscope beats a phone camera.