All hair, whether on the head, brows, the eyelashes or the unmentionables, grows in three phases. The only thing that differs between diffent types of hair, lash or head hair for example, is how long the phases take.
Follicles – the growth engine.
Each individual hair is formed inside a hair bulb deep in a hair follicle, and has it’s own growth schedule. Lashes grow and fall out one by one at completely different times. This is why we never end up losing all our eye lashes at the same time unless there’s some severe trauma. The follicle is a tiny but powerful factory. A healthy follicle produces nice strong hair. If you pull a hair out of a follicle another one will grow up in its place. If you lost your eyelashes because they were yanked out, then as long as the follicle isn’t damaged, your lashes will grow back as soon as it ends the dormant state.
Anagen – the growth phase.
Each follicle can grow many hairs over a lifetime: The phasing of the growth cycle is staggered amongst the follicles. This prevents periodic phases of baldness when the growth cycle stops.The growth phase is called ANAGEN. How long anagen lasts is determined genetically, and varies between the sexes and from one person to another. It is the length of this time that determines how long the hair will grow. For head hair, the anagen phase can last from three to as many as seven years.
Catagen – the intermediate phase.
The CATAGEN phase is a short resting phase that follows the anagen phase. This phase lasts between two and four weeks. No pigment is made during that time, and the follicle stops producing hair. The base of the follicle moves upwards towards the surface of the skin.
Telogen – the shedding phase.
The TELOGEN phase lasts for three or four months. During this time a new hair begins to grow from the hair follicle. As it grows upwards the old hair will be shed naturally or may be pulled out. Tweezing is easily and painlessly done with telogen hairs. These are the hairs that come out when you shampoo or brush your hair. Shedding is part of the normal process of the replacement of old hair with new. At any one time, around one in ten of the follicles on an individual’s head are in the shedding phase. The new hair emerges from the same opening at the surface of the skin as the old one, and the hair cycle begins again. As people age, the hair cycle can become shorter (this isn’t true for everyone and depends on your genes). The follicles gradually give up producing long, strong hair, and the hairs become thinner and shorter. This can happen to lashes, brows, leg and arm fuzz and so on.
Fun fact/myth buster: It is not true that cutting your hair makes it grow faster or thicker. Nor does shaving your legs make the hair grow coarser. The length of the growth phase and the width of the hair shaft are the results of your genes, and are not affected by anything you do to your skin or to the hair shaft itself.