You are born with all your hair follicles, about 100,000 on your scalp, and you are not able to gain any more.
There are actually two types of hair on your body. Vellous hair is the fine soft hair that covers the majority of your body, including the longer courser terminal hair that grows on your scalp.
By contrast, terminal hair grows on the face, chest, and legs in response to androgens at puberty. As well, with the loss of estrogen, for example in menopause, terminal hair may grow in women.
The hair on your head grows in four stages. About 80 per cent of the hair follicles actively grow hair for about two to six years. Then, about one to three per cent of follicles stop hair growth and degenerate for about one to three weeks.
This is followed by a three- to four-month resting phase termed the telogen stage.
The last stage of hair growth is the shedding phase which represents about 0.1 per cent of hair, or 75 to 100 hairs each day. Luckily, your hair follicles all have their own time schedule which means your scalp always has different follicles at different stages. All your hair does not shed at once!
Repeated chemical treatments, poor grooming habits, and exposure to harsh environments can cause hair texture to change and breakage to occur.
Your hair is actually comprised of filaments of proteins called keratin that grow from hair follicles. Curly, wavy, or straight hair isn’t due to the hair itself, but rather the shape of the hair follicles. Melanin is the pigment that gives your hair its colour. Grey hair is the result of the loss of melanin in older age.
Hair loss or alopecia can occur in anyone. It is not a reduction in the number of hair follicles, but rather a shortening of the growth stage of hair. Shorter, thinner hairs are produced which cover smaller areas of the scalp and bald spots result. In men, hair thinning begins at the crown and progresses to the mid-scalp area; in women hair loss begins in the central area.
Another cause of hair loss is a lengthening of the resting and shedding stages, resulting in a tripling of the number of hairs lost. The result can be a noticeable, sudden thinning.
Drugs can interrupt the hair growth cycle and cause hair loss. Cancer chemotherapy medications are the most often implicated, but other drugs include ACE inhibitors used for treating high blood pressure, the anticoagulant warfarin, drugs like levodopa used to treat Parkinson’s disease, the antipsychotic drug lithium, and the seizure medication valproic acid.
Because hormones are involved in hair growth, hormone drugs such as oral contraceptives and anabolic steroids can affect your hair.
If you have started taking a new medication and notice that your hair is shedding more than usual, don’t assume that it’s normal. Get it checked out.
Your hair’s colour, texture, and curliness are genetically determined, as is your risk for hair loss. However, many hair products and remedies are promoted to give you a full head of shiny, luxurious hair.
Shampoos are intended to remove dirt, sweat, and debris from your hair, and conditioners decrease tangles and frizz.
They are probably part of your personal hygiene routine, but keep in mind that while they will enhance your hair’s appearance, they do not make it “healthier.”
You need overall good health in order to have healthy hair.