Melanin determines skin and hair color. It also is present in the skin in varying degrees, depending on how often a population has been exposed to the sun in the past. Melanin can be found in the pupils or irises of the eyes and areas of the brain.
The sources of melanin are specialized cells, called melanocytes, found in the bottom layer of the epidermis, the base of hairs, the inner ear, the eye's iris and other locations. The synthesis of melanin in the skin is controlled by the pituitary gland, which releases a hormone that stimulates it.
Food does not contain melanin. Melanin is derived from the amino acid tyrosine. Some foods that are high in tyrosine include seaweed, eggs, cheese, fish and various game meat. A tyrosine deficiency may lead to albinism.
According to the Daily Mail, melanin pills are a type of tanning pill. Manufacturers of these pills claim that their products, such as Tyrosine, which contains the nutrient Para-aminobenzoic-acid (PABA), increase the production of melanin, resulting in a quicker and deeper tan.
Melanin in the skin can be reduced by avoiding harmful UV rays, applying good sunscreen, following home remedy solutions for existing melanin and by eating foods rich in vitamins C, E and A. A patient experiencing issues with excessive melanin production can have problems such as hyperpigmentation,
The site of melanin formation is the last layer of the epidermis. This layer is also known as the basal layer. Cells that manufacture melanin are known as melanocytes.
According to Free Science, freckles and moles are the result of a localized concentration of melanin. Both freckles and moles are generally associated with pale skin.
Melanin production is accelerated by exposing the skin to ultraviolet A and ultraviolet B sunlight, according to Mayo Clinic. Melanin also is increased by exposure to the ultraviolet light found in tanning beds and sunlamps.
According to The Journal of Nutrition, melanin and carotene are two of three pigments that determine skin color. The third pigment is hemoglobin. All three pigments are made in the epidermal layer of the skin.
The main difference between carbon-12 and carbon-14 is the number of neutrons present in each compound. Carbon-12 has six neutrons, while carbon-14 has eight neutrons, explains About.com. The differing number of neutrons is responsible for numerous differences between the two compounds.