Norwood Scale: how to classify male pattern baldness

The Norwood Scale: complete guide

The Hamilton-Norwood scale is the international standard for classifying the degree of male androgenetic alopecia. It was developed by Dr. James Hamilton in the 1950s and refined by Dr. O'Tar Norwood in the 1970s.

The 7 Norwood stages

Stage I - No significant loss

• Intact frontal hairline
• No treatment required
• Recommendation: annual monitoring

Stage II - Mild recession of temples

• Temples begin to recede symmetrically
• Minimal loss, often considered normal with age
• Recommendation: minoxidil 5% + monitoring

Stage III - First clinically significant stage

• Clearly receded temples forming an M shape
• Frontal line retreats >2 cm from the coronal crease
• Recommendation: finasteride + minoxidil + consider micro-graft

Stage III Vertex - Crown loss

• Stage III temples + loss at the crown (vertex)
• Mixed frontal + vertex pattern
• Recommendation: pharmacological treatment + consider surgery

Stage IV - Extensive frontal loss

• Deep temple recession + significant vertex loss
• Hair band still exists between frontal and vertex areas
• Recommendation: surgery recommended (2,500-3,500 grafts)

Stage V - Merging zones

• Frontal and vertex areas begin to merge
• Very thin residual hair band
• Recommendation: surgery (3,500-4,500 grafts)

Stage VI - Extensive loss

• Frontal and vertex areas completely connected
• Only lateral and back hair remains (horseshoe pattern)
• Recommendation: surgery (4,500+ grafts) + realistic expectations

Stage VII - Maximum loss

• Only a narrow band of hair remains at the back
• Limited donor area
• Recommendation: careful evaluation, possible limited surgery

Ludwig Scale (women)

For female hair loss, the Ludwig scale is used with 3 stages:

• Ludwig I: Diffuse thinning on top
• Ludwig II: Notable thinning at the crown
• Ludwig III: Near-total baldness on the upper area

How digital classification works

Modern clinics use software like TrichoSuite to:

1. Automatic classification: AI analyzes patient photos and suggests the Norwood/Ludwig stage
2. Density measurement: digital densitometry per zone (follicles/cm2)
3. Zone-based planning: each area of the scalp is analyzed individually
4. Temporal tracking: comparison of 3D scans over time

Treatments by stage

Conclusion

The Norwood scale is fundamental for standardized communication of hair loss degree among professionals and with patients. Precise classification, combined with digital analysis tools, enables optimal treatment planning for each case.