RENEE MONTAGNE, host:
Consider this statistic: More than a third of American adults under 40 now have tattoos. Lots have more than one. Now consider this: Inks used in tattoos are not regulated, and some may not be safe.
NPR's Patti Neighmond started her report at a tattoo parlor.
PATTI NEIGHMOND: At Zulu Tattoo in Los Angeles, co-owner Khani Zulu says design is just one part of the artistry. Color is the other. And at Zulu, there's a dramatic rainbow of choices.
Ms. KHANI ZULU (Zulu Tattoo): We've got light purple, dark purple, blue, sky blue, mint green, turquoise, lime green, graffiti green, nuclear green, avocado.
NEIGHMOND: Caramel, golden yellow, bright yellow, Georgia peach.
Ms. ZULU: Really, any color that you can possibly imagine, we can put in your skin.
NEIGHMOND: Safety is a big concern, says Zulu. There are inks that contain metals and plastics. So when it came to choosing a brand, she says Zulu chose the one that seemed most natural.
Ms. ZULU: All of their pigments are vegetable-based, organic pigments. And they are vegan-friendly - absolutely no animal products used. It's pretty much as safe as you can get.
NEIGHMOND: But federal health officials are concerned that not all inks are safe, and that some tattoo parlors are mixing their inks with other unsafe products.
Dermatologist Dr. Tina Alster says that's especially true when it comes to some of the trendier new tattoos.
Dr. TINA ALSTER (Dermatologist): There are some chemicals that have been shown to be injected along with the tattoo inks to make them brighter, or even psychedelic. There are some that actually glow in black light.
NEIGHMOND: And the problem, says Alster: nobody knows for sure what's really in them.
Dr. ALSTER: They just find things that can glow in the skin, and they just will inject them the same way as they inject the other inks. It's all put into the same syringe.
NEIGHMOND: And the federal agency that could regulate tattoo ink doesn't. The Food and Drug Administration says they've had more pressing public health issues, and there haven't been that many reported problems with tattoos.
FDA chemist Bhakti Petigara Harp says that may be changing. Recently, the agency started to see an increase in consumer complaints.
Dr. BHAKTI PETIGARA HARP (Chemist, FDA): We've seen such things as infections, swelling, cracking, peeling and blistering at the tattoo site.
NEIGHMOND: FDA researchers have found certain colors: red, yellow, orange and even white - may be more sensitive to sunlight, more easily broken down under skin and more problematic for the body. They found some inks migrated to the lymph nodes. That could damage the body's system of filtering out toxic organisms.
Dermatologist Alster says the same is true for ink used in permanent makeup, like tattooed eye liner, lip liner and eyebrows.
Dr. ALSTER: They often mix different tattoo inks, and a lot of them, we don't even know what's in them. We don't know what the ingredients are. There's some ingredients, like cadmium, that can be carcinogenic. There are some that cause what we say are granulomas, which is an allergic reaction in the skin.
NEIGHMOND: And there are purely cosmetic concerns, as well. Ironically, permanent tattoos intended to enhance facial features often don't age well.
Dr. ALSTER: You can have a lip-liner tattoo that easily traces a nice, full lip when you're younger, but as you get older and your lips thin, the lip liner actually is outside the border of the lip.
NEIGHMOND: And removing permanent makeup, just like removing other tattoos, is more costly and complicated than getting it in the first place. Tattoos are typically removed using a high-speed laser that vaporizes the ink particles.
Dr. ALSTER: So that when you hit them with one of these red or infrared short-pulsed lasers, they will form an insoluble pigment, they actually will get darker rather than lighter. And that's because there are small amounts of iron or titanium oxide in those tattoo inks, and they form this irreversible pigment in the skin.
NEIGHMOND: So think carefully before you get a tattoo. And the FDA says be aware of the risks. If you do have a problem, report it to the FDA website at www.fda.gov. They do have the power to take unsafe brands of ink off the market.
Patti Neighmond, NPR News.