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).
Human evolutionary developmental biology
Jeremy De Silva and Julie Lesnik examined chimpanzee neonatal brain size to identify implications for brain growth in "Homo erectus". This changed the understanding of differences and similarities of post-natal brain growth in humans and chimpanzees. The study found that there was a distinction necessary between growth time and growth rate.The times of growth were strikingly similar, but the rates were not. The paper further advocates the use of fossils to assess brain size in general and in relation to cranial capacity.