I was wondering, what is used in tattoo ink, and can it cause cancer or any other health problems?
—The Unorthodox One
Dear The Unorthodox One,
Tattoo ink is made from dyes derived from a variety of metals, which produce the distinctive colors (for example, red dyes are made from cinnabar) donned by biceps and butts everywhere.
Your concern about negative health effects from tattoo ink is not without reason. Although there has never been a documentation of cancer from tattoos or tattoo ink in the medical literature, there are known allergic reactions. In particular, the liquid that holds red and yellow inks has an increased allergic potential. There's also an extremely rare, non-allergic immune reaction to some of the dyes in tattoo ink. In addition, tattoos and tattoo ink may not cause cancer, but dark tattoo colors can make a melanoma (skin cancer) more difficult to identify (read What does a melanoma look like? in Go Ask Alice's General Health archives for more information).
FYI, "jailhouse tattoos," which involve the use of India ink to draw tattoos on the body, are safe, with no resultant cancers or other adverse health effects having been reported.
Perhaps of greater importance are the possible health problems that can result from the use of dirty tattoo needles, or from otherwise unsanitary conditions in the tattoo parlor. If there's a tattoo in your future, check out Tattoo safety guidelines in Go Ask Alice's General Health archive for some good tips about what to look for in a tattoo artist and his/her parlor. For more information, check out the related questions. You can also find information about tattoo safety at the FDA's report, "Think Before You Ink"Alice!