On average, hair tends to grow between 0.5 and 1.7 centimeters per month. This is equivalent to around 0.2 to 0.7 inches. This estimate comes from The Trichological Society. However, lots of different factors affect the speed of hair growth.
Males, for example, may find that their hair grows faster than that of females. Other things that influence the speed of hair growth include genetics, age, health, and pregnancy.
Bone marrow, which is the soft substance present inside the bones, is the only part of the body that grows faster than hair.
The lips, palms of the hands, and soles of the feet are the only parts of the body on which hair does not grow. The main purpose of hair is to protect the body and keep it warm.
Keep reading for more information on how hair grows and the various factors that affect the speed of its growth.
Stages of Hair Growth
People are born with around 5 million hair follicles. These are little pockets in the skin that hair grows out of.
Around 100,000 of these follicles are on the scalp. People with oval shaped follicles have very curly hair, while those with round follicles have straight hair.
The stages of hair growth are as follows:
Each follicle contains a hair root, which is made of cells of protein.
As blood circulates around the body, it delivers oxygen and nutrients to the protein cells, which they need to multiply.
As the protein cells multiply, they build hair, which pushes up through the skin.
As the hair grows out of the skin, it passes an oil gland. This lubricates the hair with the oil it needs to stay soft and shiny.
By the time the hair is long enough to come through the skin, it is dead. As a new hair grows underneath, it pushes the dead hair out of the skin. The hair then falls out or is shed.
Not all hair follicles are in action at the same time. Follicles on the scalp, for example, will grow hair for a few years before becoming inactive for a period. This inactive part of the hair growth cycle is called telogen.
People lose around 50–100 hairs from their body every day as part of the normal hair growth cycle.