It impacts up to 6 million people in the U.S. -- mainly women -- who can't get through the day without pain shooting through their bodies. There are very few effective treatments for fibromyalgia, so one doctor decided to try a controversial method to treat his patients. He said it works. Other dermatologists said it's dangerous.

"All I could say to my doctors is, 'I feel like I've been hit by a truck," Laura Hemrick said.

A constant, aching pain put Laura Hemrick's body and brain in slow motion.

"I see people, and I think, 'I've known you all my life, but I don't remember your name," Hemrick said.

After more than 15 tests and six months of doctors appointments, she found out she had fibromyalgia -- a chronic condition that causes widespread pain, fatigue and fogginess. Exercise provides some relief, but the drugs made her sick.

"I would deal with the pain before I go back to those again," Hemrick said.

Then, a dermatologist wrote a prescription that shocked her: spend time tanning.

"If I were to give a lecture to my dermatology colleagues about this almost certainly some would find some tomatoes to throw at me," said Dr. Steven Feldman, a dermatologist at the Wake Forest University Baptist Medical Center in North Carolina.

Feldman led a study that found fibromyalgia patients who were exposed to UV rays in a tanning bed over six weeks felt a decrease in pain compared to those who were in non UV beds. He says the UV rays cause the skin to release endorphins -- feel-good molecules that ease pain and increase relaxation. Other dermatologists say young people who use tanning beds have a 75-percent higher risk for melanoma.

"Just once using the tanning bed will give you enough DNA damage to increase your chance of skin cancer," said Dr. Shasa Hu, a dermatologist at the University of Miami School of Medicine.

Hemrick said, so far, tanning is the only thing that provides relief.

"Nothing is completely free of any possible risk," she said.

She's taking the risk because she says the alternative is to live in pain.

Hemrick spent 12 to 15 minutes three times a week in a tanning booth to ease the pain. Feldman said UV tanning beds have also been helpful in easing psoriasis. He would not recommend them for anyone who doesn't have these conditions. The idea for this started during a tanning addiction study when doctors realized patients were repeatedly going to tanning beds to ease aching backs.