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).
Ingrown hair
Ingrown hair is a condition where a hair curls back or grows sideways into the skin. The condition is most prevalent among people who have coarse or curly hair. It may or may not be accompanied by an infection of the hair follicle (folliculitis) or "razor bumps" (pseudofolliculitis barbae), which vary in size. While ingrown hair most commonly appears in areas where the skin is shaved or waxed (beard, legs, pubic region), it can appear anywhere. Anything which causes the hair to be broken off unevenly with a sharp tip can cause ingrown hairs. Ingrown hairs are also caused because of lack of natural exfoliation in the skin.