How do Tattoos Work?

Originally Published: October 5, 1995 - Last Updated / Reviewed On: July 17, 2007
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Alice,

How do tattoos work? I mean, if human skin cells are always shedding and reproducing themselves, how are the pigments of a tattoo able to stay in the skin for so long?

—MOM

Dear MOM,


The human skin is made up of two principal parts: the epidermis and the dermis. The outer, thinner epidermis consists of four or five cell layers. The inner dermis is made up of two portions: the upper, papillary region and the reticular region. Tattoos are made by inserting ink into the deepest layers (the dermis portion) of the skin, which shed cells at a much slower rate than layers closer to the surface. That is why tattoos can last a lifetime.

That is also why getting a tattoo may sometimes pose a health risk. Inserting needles deeply into the dermis layer can lead to a skin infection, or even a blood infection, if the tattoo parlor conditions are unsanitary. For more information on tattoos, call your state Department of Health for information about the legality and sanitary procedures for tattoos in your state. In New York City, tattoo artists (but not tattoo parlors) are licensed by the NYC Department of Health and Mental Hygiene. Columbia students and others living in New York City who are looking into a new tattoo, or wishing to complain about an artist or parlor, may call 311 for more information.

Alice