Natural hair color depends on the ratio of components of the natural hair pigment. This natural hair pigment is called melanin. Melanin actually means black so strictly speaking we should only use this word when talking about black hair. However, today scientists and dermatologists use the word melanin when talking about any kind of hair pigment blonde, red, brown, or black. Melanin granules are formed in the inner layer of the hair keratin fibers. The ratio of these melanin granules defines a unique natural hair color. Melanin granules are attached to the keratin fibers with the help of organic compounds - lipids, that basically "cement" these pigment granules into the hair cortex. Hair color depends on the type and quantity of the pigment, shape of pigment granules and their distribution in the hair cortex. Natural hair colors range from black (very high content of pigment) to the silver-white (almost complete absence of a pigment). All other natural shades of hair are produced by the intermediate concentrations of the pigment.

The distribution of the pigment in hair: 1 - hair pigment (melanin), 2 - hair medula; 3 - hair cortex; 4 - hair cuticula.

Hair fiber has no color, bleach any hair and the fiber looks white simply because it reflects light. Hair color is provided by melanin pigments produced by cells called "melanocytes". In humans, melanocyte cells are found diffusely scattered in the skin and also in little clusters in the hair follicles. Melanocytes respond to various stimulants to produce more or less melanin. Sunlight exposure makes the melanocytes in the skin produce more pigment and we get a tan. The melanocytes of the skin and the melanocytes of the hair follicles are essentially the same. It is thought that the melanocytes in hair follicles can act like a storage depot for supplying the skin with melanocytes. This becomes very apparent then the skin is damaged and depleted of melanocytes. Studies show the melanocyte cells migrate from the hair follicles to repopulate the melanocyte deficient skin. Melanocytes in hair follicles are primarily located in the hair bulb at the bottom of hair follicles. They sit in a group just above the dermal papilla along with the matrix cells that produce the hair fiber. For the melanocytes, this is the ideal location to produce pigment and have it incorporated into the growing hair fiber. Melanocytes produce melanin pigment proteins in their cell cytoplasm. The pigment is accumulated in membrane bound vesicles in the cell called "melanosomes". In black hair producing follicles, the melanosomes in the melanocytes are very large oval shaped and gradually become densely filled with pigment proteins. People with lighter colored hair have less melanin protein in their melanosomes. Blond haired people have melanosomes with a low density and patchy deposition of melanin. People with red and blond hair have melanosomes that are smaller and spherical in shape and the individual melanin pigment granules inside the melanosomes are also smaller. The matrix keratinocytes that produce the hair fiber cluster around the melanocyte cells. The melanocyte cells release their melanosomes to the keratinocytes through dendritic processes. The keratinocytes actively phagocytose the melanosomes (which means the keratinocytes "eat" the melanosomes by surrounding them and pulling them into the cell). Once the keratinocyte cells have melanosomes inside them they are then formed into the hair fiber and thus the hair fiber has color. Throughout the years, melanocytes continue to produce and inject pigment into the hair's keratin. giving ity a colorful hue. With age, or due to certain disorders and diseases, with a reduction in melanin production, hairs gradually start to loose their color intensity, turn gray and eventually white, or completely dicolored. It is being considered, that hair follicles have a"melanogentic clock", which slows down, or stops melanocyte activity, thus, decreasing the pigment, our hairs receive. Naturally, this always occurs just before a hair stops growing and is preparing to fall out, or shed, so we always get to see our hair roots looking pale. It is also known about different regulation of an exhaustion of the pigmentary potential for each individual hair follicle, which typically occurs at different rates and may happen more rapidly, or really slowly, primarily depending on your age and genetics.