Hair growth

Hair growth

Human hair – either too much or too little – is an important social factor in our society. Millions of people suffer from early hair loss (alopecia) and more millions, often women, suffer from unwanted hair growth (hirsutism). Presently there is no real effective and safe treatments available that are suitable for both men and women.

Human hair is built by keratin. It’s basically the same protein which builds our nails and skin. The hair is situated under the surface skin – in the follicle. The follicle follows a pattern of growth, rest and regrowth.

The growth follows three phases: anagen, catagen and telogen. Every hair follows the development phase. The growth of the single hair is approximately 1.25 cm (half an inch) per month.

The hair growth swings between activity and inactivity. Between the three main phases there are resting phases, and this may be crucial when considering regulating hair growth. The follicles represent an intricate biological structure, considering their cycles.

The three hair phases:


1. Anagen phase

The hair grows around 1.25 cm a month, and faster in the summer than in winter. The growth phase, or anagen phase, lasts an average of 3-5 years, so a full-length hair averages 46 -72 cm. The anagen phase is generally longer in Asians, and can last as much as 7 years with hair being able to grow to 1 metre.


2. Catagen phase

At the end of the anagen phase, the hair enters the catagen phase. A short transitional phase that lasts approximately 10 days.


3. Telogen phase

The resting phase or the Telogene follows the Catagen phase. During this period the single hair is resting, or more accurate inactive. The phase may have a duration between a couple of weeks to a couple of months, though normally between one to three months. The number of hair on the Telogene phase varies, but often between 7-14 %. During this resting phase the hair is still in the follicle but not growing anymore. After a while the hair sheds spontaneously through combing or hairwash. The lost hair leaves room for new hair, after which a new growthphase, the Anagene phase, starts.