Regretting that tattoo you got? Cheer up: There's a good chance a dermatologist can remove it for you -- but success is going to depend on a number of factors, including how big the tattoo is, what colors it contains and whether you smoke.

Italian researchers who treated 352 people between 1995 and 2010 say they are the first to fully explore the factors that make some tattoos harder to remove than others. Their findings were published online Monday in the Archives of Dermatology.

The doctors used the current standard procedure for tattoo removal, which involves repeated laser treatments. The devices they used are called Q-switched lasers. They say they removed 47% of the tattoos in 10 sessions and nearly 75% in 15 sessions.

But success varied. Tattoos were harder to remove if they were:

-- Big -- covering more than 12 inches.

-- Colorful -- containing colors other than black or red.

-- Old -- more than three years old.

-- On feet or legs.

-- On a smoker. Smoking may impair wound-healing processes that help clear the ink after a treatment, the researchers say.

A separate study in the journal looked at a newer laser, not yet approved by the U.S. Food and Drug Administration, and found it removed more than 75% of tattoo ink in an average of four sessions. But the study of the picosecond alexandrite laser included only 12 patients and did not directly compare it with the standard lasers. It was partially funded by Cynosure, Inc., the manufacturer.

Typical side effects for any laser treatment can include pain, redness and swelling, says Nazanin Saedi, director of laser surgery and cosmetic dermatology at Thomas Jefferson University in Philadelphia. She worked on the study of the picosecond laser when she was a fellow at SkinCare Physicians in Chestnut Hills, Mass.

Saedi says dermatologists typically charge "a couple hundred dollars" for each Q-switched laser treatment, but it can vary from practice to practice and patient to patient. She doesn't know how much the new laser treatments will cost if the device is approved.

Maybe it's a good thing that most people seem to like their tattoos: 21% of adults have at least one tattoo and just 14% regret them, according to a recent Harris Poll.

USA Today