Hair Removal

Hair Growth Cycle

Have you ever wondered about the pattern of hair growth? Well… hair has its very own cycle too.

3 major stages make up the hair growth cycle- anagen, catagen, and telogen. Think of the stages as the growing stage, intermediate stage, and resting/shedding stage. Each strand of hair is on it’s own timeline.  If your hair was in the telogen or shedding stage at once, we would all be bald at some point.

About each Stage in the Hair Growth Cycle

While the stages of the hair growth are the same, different body areas vary in time the hair is in each stage.

  • Anagen (growing) Stage is the growing phase of hair.  On your scalp, this stage typically last around 2 to 6 years and about 85% is in this cycle.
    • Fun fact about this stage: Your scalp grows about a half an inch per month while growing faster in the summer than winter.
  • Catagen (intermediate) Stage is a short transition phase between anagen and telogen stages.  Hair follicles are preparing themselves to rest and starts shrinking in size.
  • Telogen (resting/shedding) Stage is the phase in which your hair is released and sheds.  On your scalp It can last around 3 to 4 months.

The Richard-Merhag Table below shows the duration of the hair growth cycle.

Body Area % in Anagen % in Telogen
Scalp 85 15
Eyebrows 10 90
Ear 15 85
Beard/Chin 70 30
Cheeks 50-70 30-50
Upper Lip 65 35
Underarms 30 70
Bikini 30 70
Arms 20 80
Legs + Thighs 20 80
Breast/Chest 30 70

What are ingrown hairs?

Interruptions of the hair growth cycle can cause improper hair growth patterns also known as an ingrown hair.  An example of a disturbance could be waxing, plucking, shaving, threading, and other temporary forms of hair removal. As the hair starts its natural cycle, it grows normally outside the skin.  If it is removed before the hair reaches the shedding stage this causes a disturbance of the growth pattern causing the hair to grow back into the skin, i.e. an ingrown hair.  Waxing can cause the most ingrown hairs because the hair is removed very aggressively.  I think we can all agree ingrown hairs are no fun!

How the hair growth cycle effects electrolysis and laser treatments?

The most effective form of hair removal are electroloysis and laser treatments.  Treating the hair in the anagen stage is the ideal stage since this is when the hair is most vulnerable and reactive to treatments.  However as you can see from the above chart, each hair is on it’s own timeline which is one of the main reasons for multiple treatments.  For example, one of the most common areas to treat of electrolysis is eyebrows. According to Richard-Merhag’s table about 10% of the hairs are in the anagen stage at one time for an average of 4-8 weeks.  It is still important to treat the hairs in the telogen stage, although they have a higher chance of growing back as the follicle is resting. With laser, the same theory takes place.