Hair, the characteristic, tough, threadlike outgrowths of skin found on many mammals, including humans. In some animals, such as hedgehogs and porcupines, it has been modified into hard spines that serve as a form of protection. In others, such as a lion’s mane or grizzly bear’s fur, it acts to help regulate body temperature and provides some protection from physical damage like scratches and bites. Hairs on the face of humans, such as eyelashes and eyebrows, provide moderate protection against dust and sweat. They also play a part in non-verbal communication and expression, such as conveying emotions such as sadness, surprise or happiness.
Hair is 95% keratin, a fibrous protein in the shape of a helix. Each hair grows from a small follicle within the surface of the skin. Tiny blood vessels supply these follicles with nutrients. Once the hair has pushed its way to the surface of the skin, these blood vessels stop feeding it and the strand of hair is no longer alive.
As the strand of hair matures and develops, it turns from a living cell into a non-living fiber. This process is called keratinization. As the hair is pushed out of the follicle and into the world, it is covered in sebum (say: sheb-ooz), an oily substance produced by glands on the skin called the follicles. The follicles are located on the scalp, arms, genital regions, and in some males on the face and chest. The sebum from these glands keeps the hair moist and supple but it can also make the head look greasy if there is too much of it.
There are about 100,000 hairs on the human head, and we lose about 50 to 100 of them each day, whether we’re brushing or combing our hair, getting a haircut or just sitting still. New hairs continually replace those that have been shed.
Hairs on the head grow at a rate of about 0.5 inch (13 mm) per month. Other hairs on the body develop at different times and in different places: some in the armpits, genital areas, and on the trunk and limbs; some in the face, such as eyebrows, eyelashes, and a beard in men; and some on the lips and cheeks of both genders.
It’s important to know how to properly care for your hair and keep it healthy. Having healthy hair not only gives you a sense of pride and self-esteem, but it can also protect you from disease. In addition, hair can be used as a marker of culture or societal standing and, for better or worse, has been associated with a variety of stereotypes. This is why it’s crucial to take the time to learn how to style your hair and treat it with care. It can accent your good features and hide bad ones, highlighting your best attributes. If you’re not sure where to start, ask your stylist for some ideas. They will be happy to help you create a look that fits you.