Norwood Scale

The progression of male pattern baldness is generally classified on the Hamilton-Norwood scale, which ranges from stages I to VII.

This measurement scale was first introduced by Dr. James Hamilton in the 1950s and later revised and updated by Dr. O'Tar Norwood in the 1970s.

There are seven levels of loss in the Norwood scale:

• Norwood 1 - Normal head of hair with no visible hair loss.
• Norwood 2 - The hair is receding in a wedge-shaped pattern.
• Norwood 3 - Same receding pattern as Norwood 2, except the hairline has receded deeper into the frontal area and the temporal area.
• Norwood 4 - Hairline has receded more dramatically in the frontal region and temporal area than Norwood 3 and there is the beginnings of a bald spot at the back of the head.
• Norwood 5 - Same pattern as Norwood 4 but much reduced hair density.
• Norwood 6 - The strip of hair connecting the two sides of the head that existed in Norwood 4 and 5 no longer exists in Norwood 6.
• Norwood 7 - Shows hair receding all the way back to the base of the head and the sides just above the ears.