id LAB: The Secret Chemistry of Tattoos

Why getting inked is a declaration of war against the body

About a quarter of Americans have at least one tattoo. But what does that really mean for the skin? Fact is: The first pinprick initiates a biological process that will keep the body busy for a lifetime— and which even doctors still don’t completely understand…

Throughout the room a highly distinctive buzzing prevails. Multiple 0.3- mm needles are barely piercing Robert C.’s skin—50 times every second. They are arranged to form a small but high-strength brush with “hairs” made of high-quality stainless steel. Ink is held in between needle points. Pulse by pulse the tattoo machine “hammers” the liquid roughly 2 mm deep into the skin. About an hour and approximately 150,000 strokes later the tattoo artist’s work is done, but for Robert’s body the work has only just begun. And it will continue until the end of his life…

Every square centimeter of the tattooed portion of Robert’s body has been injected with about 1 mg of ink. So a tattoo spanning about as much surface as the cover of a paperback book weighs 0.2 grams, but depending on the technique used and skill of the tattoo artist, it can weigh up to nine times as much. The immune system’s first reaction is large-scale inflammation visible as redness of the skin around the injection sites. It has suddenly found foreign substances and wants to get rid of them—as soon as possible.

DOES THE BRAIN PERMIT TATTOOS?

The removal of the pigments’ watersoluble carrier substance poses no problem: The dermis, the layer of skin that is the ultimate destination for the thousands of ink injections, contains blood and lymph vessels. More difficult to deal with are the colors themselves: They consist of a very fine powder that is virtually insoluble in water. The immune cells known as macrophages can wrap around and carry away the smallest particles, which leads to the image fading over time. “Within 42 days, around 30% of the tattoo pigments have already migrated to other parts of the body,” explains Peter Laux of Germany’s Federal Institute for Risk Assessment, a government agency that has investigated the possible health consequences of tattoo ink. But to where in the body could such materials migrate? At less than one ten-thousandth of a millimeter thick, the tiniest of their constituents are nanoparticles. Michael Landthaler, the former head of dermatology at University Hospital Regensburg, is convinced: “They end up throughout the body—for example, in the liver, brain, and kidneys.” So what should merely decorate the skin may well begin a second life within the skull. Pathologists at the dissection table observe evidence of the mobility of pigments: The lymph nodes in the vicinity of a tattoo tend to change their color in accordance with the dominant hue, so these ordinarily white filter stations of the body may end up tinted red, green, or black.

What most people don’t realize: Although pigments used in tattoos, which include colorants used for the application of permanent makeup, are considered color additives by the FDA and so require pre-market approval under the Federal Food, Drug, and Cosmetic Act, the agency admits it hasn’t exercised regulatory authority over the color additives used in tattoo inks. If a problem is brought to the FDA’S attention it will investigate, but generally tattooing is regulated by local jurisdictions.

More than 50 hues and pigments are in use, and the list is growing.

“IT’S LIKE A HUMAN EXPERIMENT”

And although there are some color additives that have been approved for use in cosmetics, none of them has been approved for injection into the skin. In fact, there is a host of pigments that are used in tattoo inks that are not actually approved for contact with skin at all, some of which would be more appropriate in printers’ ink or paint for vehicles. In theory, anyone can mix and sell ink—as long as the ingredients are listed on the label and no banned substances are used.

A problem with regard to testing: Since color additives are tested for safety in cosmetics that are applied to the skin, many of the substances can be approved for such a use— since there’s a protective epidermal barrier between them and the inside of the body. But no one knows what happens when they enter the body. “No institution has systematically tested the dangerousness of these pigments,” reveals Andreas Luch from the Federal Institute for Risk Assessment. In the end, tattoos are a matter of choice. In other words, the fact that inks are not prohibited doesn’t mean that they’re harmless substances. Perhaps harmless inks do exist, but we don’t know exactly which ones they are. “The risk lies entirely with the consumer. It’s like a human experiment,” says Luch.

DOES SUNLIGHT TRANSFORM A TATTOO INTO A CHEM LAB?

The number of people taking part in this experiment is steadily growing: In the U.S. alone, nearly one in three people under age 30 has a tattoo. Tattoo fans see the many prominent athletes and musicians with tattoos as proof of the harmlessness of the body art. And to date, not a single case of cancer has been definitively attributed to tattoos. “However this comes as no surprise: Large health surveys have not taken into account whether or not a person is tattooed,” says medical researcher Peter Laux. “However polls show that about 9% of tattooed people have permanent health problems—the real figure is likely higher because some people may be reluctant to admit it.”

The most common complaint is allergies, which sometimes do not develop until months or even years later. An allergy may develop to any of the classic pigment compounds: chromium ( green), mercury ( red), cadmium (yellow), and cobalt ( blue). Although modern ink manufacturers try to avoid the heavy metals, these remain on the market: Brown color pigments are often contaminated with nickel—a heavy metal that is considered to be the most common cause of contact allergies. But most allergies are now to red, a color with yet another weakness—sunlight. “UV rays cleave certain pigments,” says Laux. The fading of the image and a slight tingling sensation of the skin are among the more harmless consequences, while most serious is the formation of cell- damaging and even carcinogenic substances. According to surveys, about one in five tattooed people exhibits health problems associated with sunlight, which can only be curbed by using a strong sunscreen. But sometimes even that does not help: Boils and persistent inflammation can occur, which in extreme cases may require surgical removal of affected skin.

The major allergic potential is not particularly surprising, since after all the pigments do not come from the pharmaceutical labs or cosmetics producers, but rather from industry. For example, black is derived from burned chemicals—so, in principle, the same carbon black that’s used to dye tires. Colored pigments have been developed for many purposes: vehicle paint, furniture, textiles, and ink cartridges—but these aren’t approved for use in the body. Getting “marked for life” isn’t a decision to take lightly…

“EVERY THIRD AMERICAN UNDER 30 HAS A TATTOO”