Not everyone’s goal in their hair journey is to achieve long hair, but for those who do long for lengthy locks, understanding the hair growth cycle is extremely helpful. Like everything else involving our bodies, there is science behind the health of our hair that can help us on our journey to growing healthy, long natural hair.
Hair is comprised of two distinct parts – the actual follicle, which is in the dermis layer of the skin and contains the living portion of hair and the shaft which is the portion we see above the scalp. The hair shaft is not a living structure and is comprised of keratinized epithelium. The bulb, however, is comprised of cells that divide every 23 to 72 hours. For hair on the scalp this translates to 0.5 inches of hair growth month or six inches per year on average. For mammals other than humans, hair growth is seasonal or cyclical. Our hair growth, however, occurs in three concurrent stages at once. All over our head, hair is found in one of three stages of the hair growth cycle – click to enlarge image below.
The anagen stage of the hair growth cycle is also known as the growing or active stage. During this phase, cells that are nourished by tiny blood vessels in the scalp rapidly divide in the papilla which pushes hair up the follicle. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active state of the hair growth cycle for anywhere from two to six years; about 85 percent of the hair on your scalp is in the anagen stage at any given time. The potential length of your hair is directly proportional to the length of the anagen stage of the growth cycle; therefore women who have trouble growing their hair beyond a short length may have a shorter growing stage. Conversely, women who have incredibly long lengths may have longer anagen phases.
There are two proposed methods to grow longer hair by affecting the anagen phase:
- Increase the speed of cells dividing during this phase: This is usually done by increasing the amount of nourishment via blood flow to the papilla of the hair follicle. Scalp massages, essential oils and the inversion method all increase blood flow which can speed up cell divide. In addition to physical stimulation, a well-balanced diet consisting of vitamins and nutrients and regular exercise affects the length of the anagen phase of the growth cycle.
- Extend the amount of time hair spends in this phase: This is usually accomplished by internal methods such as taking MSM, a supplement said to extend the amount of time hair spends in the anagen phase. Also surprisingly melatonin, according to researchers at Frederich-Schiller University in Germany, also prolongs the length of time hair spends in the growth stage of the hair cycle. Most ladies opt for a healthy hair vitamin that includes MSM, along with biotin and other supplements to aid in faster, stronger hair growth. My personal favorite is Nouritress hair vitamins plus.
The body internally signals for hair to progress from the anagen to the catagen phase of the hair growth cycle. This phase is also known as the transitional phase and is characterized by a slight loss in hair color (melanin production is ceased). During the approximate two weeks of the catagen phase, the hair follicle shrinks, detaches from the blood supply and the papilla pushes upward.
This is known as the resting phase, where the follicle remains dormant for one to four months. Ten to fifteen percent of the hairs on one’s head are in this phase of growth.
The exogen phase of hair growth is sometimes lumped together with the telogen phase of the growth cycle, but they are actually two separate stages. The exogen phase is the period where the follicle detaches and sheds from the scalp. Hair sheds an average of 80 strands per day (50 – 100, but sometimes up to 150 strands) in a healthy person. Decreasing the amount of shed hair is also a method women take to increase hair growth. While it does not directly affect the growth stage of the hair cycle, a reduction in the amount of shed hair will make hair fuller and appear thicker.