Human skin color effects of tanning. Around the same age, women experience darkening of some areas of their skin. Human skin color fades with age. Humans over the age of thirty experience a decrease in melanin-producing cells by about 10% to 20% per decade as melanocyte stem cells gradually die. The skin of face and hands has about twice the amount of pigment cells as unexposed areas of the body, as chronic exposure to the sun continues to stimulate melanocytes. The blotchy appearance of skin color in the face and hands of older people is due to the uneven distribution of pigment cells
Biological pigment changing cells that are directly stimulated by central motor neurons. They are primarily used for quick environmental adaptation for camouflaging. The process of changing the color pigment of their skin relies on a single highly developed chromatophore cell and many muscles, nerves, glail and sheath cells. Chromatophores contract and contain vesicles that stores three different liquid pigments. Each color is indicated by the three types of chromatophore cells: erythrophores, melanophores, and xanthophores. The first type is the erythrophores, which contains reddish pigments such as carotenoids and pteridines. The second type is the melanophores, which contains black and brown pigments such