Chemotherapy, or chemo, is the use of drugs to stop or slow the growth of cancer cells.
Cancer cells tend to divide very quickly—at a much higher rate than most of the cells in the body. They ignore the signals and mechanisms that tell normal cells to stop dividing.
Some normal cells in our bodies also rapidly divide, like hair follicle cells, the mucous membrane cells lining of the digestive tract (mouth, throat, stomach, intestines), and the blood-producing cells in the bone marrow.
Chemotherapy drugs work by targeting rapidly dividing cells. They damage the genetic material inside cells (RNA and DNA) that guide cell division. Chemotherapy drugs cannot tell the difference between these normal, rapidly dividing cells and cancer cells, so the drug affects these cells as well.
The hair follicles have a good blood supply, which unfortunately allows chemotherapy drugs to reach them efficiently. About 65% of people who receive chemotherapy will experience hair loss. The amount of hair loss can depend on which chemotherapy agent is used, as well as the timing, dose, and route of administration. It can also vary from person to person, and it's hard to predict who will be affected most.
