The Norwood Hamilton Scale is a code used by Hair Transplant doctors and trichologists to measure the extent of male pattern baldness and it is the generally accepted standard when describing hair loss in general.
This scale is introduced by Dr James Hamilton in 1950s and updated by Dr O’Tar Norwood in the 1970’s. He modified the stages and added 3a, 3 vertex, 4a and 5a.
Men lose their hair in different patterns. Some may lose the hair from temples, some from hair loss at the back of the head called vertex and some may have a receding hairline and at the same time hair loss at the back.
Whenever hair loss type is higher on the scale, his options are limited for hair loss treatment. For example, Minoxidil (Rogaine) and Finasteride can’t be used anymore for the hair loss type 5 and over.
Stage 1 consists on minor or no recession of the hairline. Therefore, ther is no need for hair loss treatment. However, if you have a family history of baldness, you will need to monitor your case closely and decide the appropriate time for the treatment with an expert.
It consists on triangular and typically symmetrical areas of recession at the front temporal sides with a small amount of hair loss (less dense) also in the central front part of the scalp. At this stage, we advice you to identify the reasons of hair loss.
Starting from stage 3, we can start to talk about baldness as it is t lowest extent of hair loss. A deep symmetrical recession in the temples are clear.
With stage 3 vertex, a small amount of hair loss in crown area may also occur in this stage .
It’s a moderate level of hair loss which consists on a recession in the front temporal sides and a decisive lack of hair on the crown (vertex area). Starting from hairline to the crown, in the middle of the scalp, there are natural hairs with moderate density.
A large amount of hair loss at the vertex region is clearly shown in Stage 5. The hair loss is still separated from the front temporal region but the division is much less distinct. However the balding at temporal and vertex region are larger than before and the band of hair extending across the crown is noticeably narrower and thinner.
Now we can talk about large area of balding and considerable amount of hair loss where the bridge of hair that once crossed the crown is been lost with only sparse hair remaining. The front temporal and vertex regions are now joined into one area. Hair loss on the sides are increased more.
This is the last stage and the most advanced form of baldness. Only a band of hair in a horseshoe shape is available at the back of the head from one side to the another. Since the open area is very large, hair transplant will be partial and only cover a certain part. This kind of baldness may require more than one session of hair transplantation.