“I’d love to stop tanning, but I can’t,” said Madison, who asked that her last name not be used because she felt self-conscious about the issue. “Confidence is such a touchy aspect of a girl’s life. It takes a lot of time and practice. I’m just not there yet.”

The C.D.C.’s national youth survey found that indoor tanning often goes along with binge drinking and unhealthy weight-control practices. Among teenage girls, it was associated with illegal drug use and having sex with four or more partners, and among boys with the use of steroids, daily cigarette smoking and attempted suicide. Boys also tan indoors, but their numbers are a small fraction of the total.

Some experts say combating the problem is a matter of raising awareness about the dangers of tanning. But many women said in interviews that they were aware of health risks but cared more about how they looked now.

“If I get skin cancer I’ll deal with it then,” said Elizabeth LaBak, 22, a student at Westfield State University in Massachusetts. “I can’t think about that now. I’m going to die of something.”

The Van Dresser twins in Florida say they slather their moles with sunscreen before they get in a tanning bed. They even joined a melanoma awareness club in their high school. But the pressure to be tan is strong, and they find it hard to resist. “It’s what teens do,” Samantha said. “Especially in Florida.”

The new state laws restricting tanning by teenagers seem to be having some effect. According to Dr. Guy, the C.D.C. researcher, female students in states that require a combination of parental permission or other age restrictions are 40 percent less likely to tan indoors. Ms. LaBak, the college student from Massachusetts, said fewer women on campus tan now. “All the Victoria Secret models are pale now,” she said.

Even so, salons persist. About half the country’s top 125 colleges have tanning beds on campus or in off-campus housing, University of Massachusetts medical school researchers reported in October. But Ms. LaBak’s favorite spot, Beach Club Tanning, a salon in a strip mall next to a CVS and a Big Y grocery store that offered $2 tans, has closed, and “now there’s no place that’s cheap enough,” she said.

“The tanning thing is like the smoking thing,” she said. “Everyone used to smoke. And then they said, ‘You’ll die of lung cancer.’ That’s what’s happening to tanning.”