What Is the Hamilton-Norwood Scale?

The Norwood scale, also known as the Hamilton-Norwood classification system, is a system used by hair loss specialists to determine the stage of male pattern baldness in a patient. Understanding the Norwood scale is a great way to identify hair loss in yourself; however, it is highly recommended to speak with an expert for the most accurate evaluation.

Baldness of a young man by Evg Zhul

Hamilton-Norwood Scale Background

The Hamilton-Norwood scale was developed by James Hamilton and O’Tar Norwood. James Hamilton first introduced his classification system in 1951. He developed it by observing male pattern baldness in over 300 men and used his findings to outline a common progression of hair loss. O’Tar Norwood then improved that classification system in 1975. Norwood observed 1,000 males and determined that Hamilton had left out a few rare patterns in his scale.

He added the Type A variant to the classification system — a similar hair loss progression with some differences. The combination of Hamilton’s and Norwood’s work led to the creation of one of the most popular and widely used hair loss classification systems.

The Male Pattern Baldness Stages

The Hamilton-Norwood scale is used to determine the extent of balding, treatment options and treatment success. The majority of men lose their hair in common patterns, and the Norwood scale makes it easier to identify which stage a patient is at in his hair loss. There are seven stages of male hair loss that outline the beginning stages, from progressive thinning all the way to hair loss in affected areas. Stage one is no hair loss and seven is considered bald.

Stage 1

There is minimal to no recession of the hairline.

Stage 2

This involves triangular, often symmetrical, areas of recession at the front of the head near or at the temples. This is often referred to as a “mature” or “adult” hairline and marks the end of a teenage or adolescent hairline.

Stage 3

The triangular recessions have progressed to the point of being considered balding. There is little to no hair in these deep recessions, and this is considered the beginning of the receding hairline stages.

Stage 3 Vertex

This stage is different from the first stages because the hair loss is beginning at the vertex of the head. There may be slight recession at the front; however, this type of hair loss primarily begins at the vertex.

Stage 4:

In stage 4 of the Hamilton-Norwood scale, we begin to see significantly more recession at the front of the head and the vertex. There is a rather dense band of hair separating these two sections.

Stage 5:

The front hairline and vertex recession continues to deepen. The band of hair separating these two sections begins to lessen and balding at the crown begins.

Stage 6:

The recession areas have grown more sparse, with the vertex and frontal areas joining together now. There is also a more noticeable balding crown at this stage.

Stage 7:

This is the most progressed stage of hair loss, and only a narrow band of hair now remains, typically on the sides and back of the head.

The Type A Variant

These receding hairline stages are very common; however, Norwood observed another common progression of hair loss. The Type A variant defined by Norwood is different from the seven stages outlined above in two major ways. First, the hair loss progresses from front to back with no island developing in the front first. Secondly, there is no vertex hair loss happening simultaneously.

Men's hair is a top view close-up by Estrada Anton

Frequently Asked Questions About the Hamilton-Norwood Scale

Q: Is Norwood 1 Balding?

A: The first stage in the Hamilton-Norwood scale, sometimes referred to as Norwood 1, is not balding. This is essentially the control stage in which a male has a full head of hair with very little to no signs of hair loss.

Q: At Which Stage Do You Recommend Treatment?

A: The first three stages of the Norwood scale tend to cause a bit of confusion. Since this scale is a classification system for male pattern baldness, many believe that every stage is an indicator of hair loss; however, that isn’t quite right. Norwood 1 is the control stage, where no hair loss is present. Norwood 2 is regarded as the “mature” hairline stage. What this means is that a man with a Norwood 2 hairline is simply experiencing the transition from a teenage hairline to an adult one. This does not indicate hair loss, and treatment is not recommended. Norwood 3 marks the true beginning of the receding hairline stages. If you meet the Norwood 3 criteria, hair loss treatment will most likely be recommended.

Treating hair loss early is one of the best ways to slow down the receding hairline process. If you believe you are starting to lose your hair, request a consultation with us, and we can evaluate what stage you are at and the best treatment option for you.