Re: pigment loss due to bleaching agents

Rich,

In general there are two types of skin bleaches, one contains the chemical “hydroquinone” and the other contains “monobenzone”. Those that contain hydroquinone are usually reversible, those containing monobenzone are irreversible.

The pigment in skin and hair that gives them their color is due to “melanin”. Melanin is produced in special cells in the skin called melanocytes. There are about one melanocyte for every 30-40 skin cells. The melanocytes are in contact with the skin cells and transfer to them the melanin in little droplets.

It is the amount of melanin in the skin cells that determines the pimentation of the skin or hair. The absolute number of melanocytes in the skin is the same for both sexes and all races. Differences in color among the races result from differences in the number of melanin droplets, size and rate of degradation of the melanin droplets in the skin cells.

Tanning is the result of ultraviolet light which increases the overall amount of melanin in the skin cells. Some hormones and aging also affect the pigment in skin and hair.

Hydroquinone interferes with the production of melanin and acts as a bleaching agent. The depigmentation can be reversed by discontinuing the product and by exposure to sunlight. Monobenzone can cause destruction of the melanocytes which is irreversible.