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What Is the Norwood Scale?

Medically Reviewed by Dan Brennan, MD on June 21, 2021

‌‌If you've noticed your hairline receding, you may have patterned baldness, which is also called patterned hair loss. There are many grading systems used to rate hair loss in both sexes, and the Norwood scale is used specifically for measuring male patterned baldness. It assesses the severity of your condition and also looks at factors that may contribute to your hair loss.

Understanding Hair Loss

The Norwood scale, sometimes called the Hamilton-Norwood scale, outlines seven stages of hair loss that may affect you.

Stage one. Hair loss is not significant, and your hairline is not visibly receding.

Stage two. You may notice hair loss around your temples. This is often referred to as an adult or maturing hairline and isn't yet significant.

Stage three. At this stage, your hair loss is significant, and balding becomes obvious. Your hairline recedes deeply near your temples causing your hairline to look like the letters M, U, or V. Your hair may be thinning, or you may be completely bald in those areas. In some cases, you also begin to lose hair around the crown of your head.

Stage four. You have little or no hair along the top middle of your head, also called the vertex. Hair loss increases at your temples and the crown of your head, but there is still a thin line of hair that distinguishes the two areas from one another. You also have hair that is a normal thickness on the sides of your head.

Stage five. The band of hair separating your temples and the crown of your head is smaller, and the hair is thinning significantly. 

Stage six. The separate areas of hair loss are no longer divided by a band of thinning hair. All hair on top of your head is completely gone or very sparse.‌

Stage seven. The only hair remaining on your head is a band that goes around the sides and back of your head. Your remaining hair may be thin or sparse.

Hair Growth Phases

Each hair on your head grows in three different cycles:

  • Anagen phase – This is the phase when your hair grows and may last anywhere from two to eight years. At any given time, 85-90% of your hair is in the growing phase. 
  • Catagen phase – This phase lasts two to three weeks and is when your hair follicles shrink.
  • Telogen phase – For two to four months, your hair rests. When the phase is over, your hair falls out and is replaced by a new hair.‌

Other hair on your body like arm hair, leg hair, eyelashes, and eyebrows has a much shorter growing phase. Hairs on your body typically only spend a month growing. At any given time, you are losing and growing hair, but hair loss becomes a health concern when it’s noticeable. 

Reasons for Hair Loss

You may lose hair because of genetic or environmental factors. Three common hair loss diagnoses include:

  • Anagen effluvium – Medication you take may cause you to lose hair. An example of this is chemotherapy. 
  • Telogen effluvium – You have a large number of hair follicles that reach the resting phase at one time.‌
  • Androgenetic alopecia – This is the type of patterned baldness measured using the Norwood scale. Your hair begins thinning in predictable stages of loss on the top and sides of your head. 

Treating and Preventing Hair Loss

There is no cure for hair loss. However, treatments may help slow down your hair loss stages or stimulate some regrowth. If you lose hair because of environmental factors or medications you take, treatment options may work better.

For people who lose hair due to age or genetics, treatments don’t tend to work as well. You may need to consistently use treatments over a long period of time to maintain results, or you’ll lose hair again.‌

Hair loss myths. There are many myths about what causes hair loss. As you navigate treating or preventing hair loss, it’s important to separate fact from fiction. The following myths about hair loss are not true:

  • You lose hair from using too much shampoo
  • You lose hair because you colored or permed it
  • You have dandruff, and it causes permanent hair loss
  • Hats and wigs lead to permanent hair loss 
  • You’re stressed, and it causes permanent hair loss
  • Shaving makes your hair grow back thicker
  • Turning your head upside down increases circulation and stimulates hair growth‌
  • Brushing your hair a certain amount makes it healthier

Many people choose to wear wigs or hairpieces. Others pursue surgery to implant hair from other places on your body. Keep in mind that vitamins and herbal remedies are not scientifically proven to treat or prevent hair loss. You should always talk to your doctor before beginning an at-home treatment.

Show Sources

SOURCES:

Better Health Channel: “Patterned hair loss.”

Cleveland Clinic: “Hair Loss in Women.”

Journal of Cutaneous and Aesthetic Surgery: "Classifications of Patterned Hair Loss: A Review."

International Society of Hair Restoration Surgery: "Hair Loss and the Hair Growth Cycle."

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