By age 50, roughly half of all men have visible hair loss — by 70, about 80 % do. The cause is almost always the same: androgenetic alopecia, a genetically driven loss caused by follicle sensitivity to DHT (dihydrotestosterone).
The Norwood-Hamilton scale has been the clinical standard since 1975 for grading the stage of loss across 8 levels. This article explains the scale, the most common causes, and which treatment makes sense at which stage.
What is the Norwood-Hamilton scale?
James Hamilton was the first to systematically describe the typical patterns of male hair loss in 1951. O'Tar Norwood extended the scheme in 1975, adding intermediate stages — most notably the important stage 3-vertex, where the crown is affected in addition to the frontal hairline.
Today the scale is used worldwide in dermatology, clinical research and hair transplantation. Reproducibility between self- and clinician-rating is kappa 0.77–0.82 (very good).
The 8 stages at a glance
| Stage | Description | Action |
|---|---|---|
| 1 | Youthful hairline | Monitor |
| 2 | Mature hairline, slight temple recession | Photo baseline |
| 3 | M-shape, clinically relevant | Minoxidil / finasteride |
| 3-vertex | M-shape plus crown thinning | Combination therapy |
| 4 | Deep recession + vertex | Therapy ± transplant |
| 5 | Zones merging | Evaluate transplant |
| 6 | Hair band lost | Transplant / SMP |
| 7 | Horseshoe only | SMP / acceptance |
Why men lose hair — the biology
The central player is DHT (dihydrotestosterone) — a potent androgen produced from testosterone by the enzyme 5-alpha-reductase. In genetically sensitive follicles (mainly at the front and crown), DHT binds to androgen receptors and triggers a stepwise miniaturisation: the hair cycle shortens, new hairs come in thinner and shorter until the follicle stops producing altogether.
Importantly, the hair at the back and sides — the future donor area for transplants — is genetically DHT-resistant and almost always preserved. That is the biological reason hair transplantation works at all.
Heredity: Male pattern baldness is roughly 80 % genetic. The maternal line is not the only contributor (a common myth) — studies show meaningful contribution from both parents.
What actually works — evidence-based
Topical minoxidil 5 %
FDA- and EMA-approved. Extends the growth phase and stimulates blood flow to the follicle. Visible effect after 3–6 months, lifelong use — when you stop, loss returns. Outcomes: 60–70 % halt the loss, 30–40 % see visibly denser hair.
Oral finasteride 1 mg
Inhibits 5-alpha-reductase, lowering DHT by ~70 %. In trials it stops loss in 90 % and improves density in 65 % of men. Prescription-only. Side effects (libido, mood) in 1–3 %, mostly reversible — discuss with your doctor first.
Hair transplantation (FUE / FUT)
Reasonable from stage 3–4 once loss is stable. FUE harvests individual follicular units — minimal scarring, longer surgery. FUT takes a strip and divides it — denser yield, visible scar. Realistic outcome: not a teenage head of hair, but an aesthetically dense hairline.
Scalp micropigmentation (SMP)
Tattoo-like dots simulate stubble — especially useful for stages 6–7 or to complement a transplant. No regrowth, but a visually denser appearance with short hairstyles.
Find out your Norwood stage now
4 questions, instant Norwood-Hamilton stage, anonymous and no sign-up — runs entirely in your browser.
Take the assessment for free →When to see a doctor
Norwood stages describe typical androgenetic alopecia. For sudden, patchy or episodic loss, see a dermatologist — other causes need to be ruled out:
- Iron deficiency (especially in vegetarians and athletes)
- Thyroid disorders (hyper- and hypothyroidism)
- Alopecia areata (autoimmune patchy loss)
- Telogen effluvium (stress, surgery, high fever 2–3 months earlier)
- Medications (chemotherapy, beta-blockers, some antidepressants)
Related calculators
Men's health is interconnected — beyond the hair status it's worth checking your testosterone level (rule out hypogonadism), the IIEF-5 erectile function test and your biological age as a holistic marker.
Bottom line
The Norwood-Hamilton scale gives you a clear language for a topic many men experience in silence. Knowing your stage early (typically 2–3) gives the best odds of stopping loss with minoxidil or finasteride. Use our Norwood calculator for an anonymous self-assessment — and bring concerning stages to a dermatologist.