Hair care
Scalp hair grows, on average, at a rate of about 1.25 centimeters per month, and shampoos or vitamins have not been shown to noticeably change this rate. Hair growth rate also depends upon what phase in the cycle of hair growth one is actually in; there are three phases. The speed of hair growth varies based upon genetics, gender, age, hormones, and may be reduced by nutrient deficiency (i.e., anorexia, anemia, zinc deficiency) and hormonal fluctuations (i.e., menopause, polycystic ovaries, thyroid disease).
Hairdresser
Occupationally, hairdressing is expected to grow faster than the average for all other occupations, at 20%. A state license is required for hairdressers to practice, with qualifications varying from state to state. Generally a person interested in hairdressing must have a high school diploma or GED, be at least 16 years of age, and have graduated from a state-licensed barber or cosmetology school. Full-time programs often last 9 months or more, leading to an associate degree. After students graduate from a program, they take a state licensing exam, which often consists of a written test, and a practical test of styling or an oral exam. Hairdressers must pay for licenses, and occasionally licenses must be renewed. Some states allow hairdressers to work without obtaining a new license, while others require a new license. About 44% of hairdressers are self-employed, often putting in 40-hour work weeks, and even longer among the self-employed. In 2008, 29% of hairstylists worked part-time, and 14% had variable schedules. As of 2008, people working as hairdressers totaled about 630,700, with a projected increase to 757,700 by 2018.