The Norwood scale is the standard measure of hair loss progression in men. Androgenetic alopecia (also called male pattern baldness) typically follows a distinct pattern and the Norwood scale captures the various stages of its progression. Level 1 on the Norwood scale describes someone with minimal to no hair loss. At the other end of the scale is Norwood 7, which describes someone who has lost all the hair from the top of their head, leaving just a thin ‘horseshoe’ of hair at the back and sides. Understanding where you are on the Norwood scale is important as it will help determine which hair loss treatments are most suitable.
At this stage there are no visible signs of hair loss. The hairline and crown are intact, with no signs of miniaturisation.
If you have a history of androgenetic alopecia in your family, it may be worth keeping an eye out for any signs of recession at the temples or any decreases in hair density. It is far easier to maintain hair than regrow it, so if you do notice any changes, it’s important to act quickly.
The first sign of hair loss is often a receding hairline at the corners.
It is natural for a man’s hairline to change shape between the ages of 17 and 29. This process is the transition from a juvenile hairline to a mature hairline and is nothing to do with androgenetic alopecia. For some, this transition may be more evident than others.
However, if hairline recession continues (Norwood 2), this may be a sign that you’ll go on to develop further hair loss.
For some, hairline recession affects the central part of the scalp too (Norwood 2V).
When hair loss first becomes evident, this is the best time to act.
As hair loss progresses, the hairline continues to recede further back.
For some, hair loss is most evident at the temples, creating a sharp ‘widows peak’ hairline with an ‘island’ of hair in the centre (Norwood 3).
For others, hairline recession is more uniform (Norwood 3A). This may also be the point at hair becomes noticeably thinner at the vertex (crown) area as well.
At Norwood 4, hairline recession becomes increasingly severe.
Treatment options at this stage become increasingly limited. It is far more difficult to regrow hair than maintain it. Often, a hair transplant is the only option to regain a full head of hair.
By this stage, there is little hair left on the top of the head.
The bald spot at the vertex may meet with the receding hairline at the front (Norwood 5A). Otherwise, there is only a sparse ‘bridge’ of hair separating the two balding areas (Norwood 5 and 5V).
At Norwood stage 6, the top of the scalp is now completely bald.
The remaining hair forms a distinctive ‘horse shoe’ at the back and sides of the head.
At this stage, a hair transplant is the only viable option to regain the appearance of a full head of hair. Even the strongest prescription medications – such as dutasteride – are unlikely to make a cosmetically appreciable difference.
Norwood 7 is the most extreme form of androgenetic alopecia.
The ‘horse shoe’ area of remaining hair shrinks in area as hair loss progresses from the top of the hair to the sides as well.
Any hair left at Norwood 7 is genetically resistant to further hair loss. This means it can be used as donor hair in hair transplant surgery. However, because hair loss is so advanced at this stage, the number of grafts available will be limited.