Comparing Zeltiq with Zerona

Doctors and patients alike are excited by the prospect of having new technologies that can attack fat without surgery. It is too early, however, for consumers to know how effectively either device works. That hasn’t stopped men and women unhappy with back fat and muffin tops from paying thousands for treatment in recent months.

“It’s so freaky, this can’t work,” Kate Killgore, 37, of Los Angeles, recalled thinking about the Zerona laser. But after 12 treatments in a month last summer, costing $3,400, she lost 11 inches from her waist, thighs and hips. She has maintained her new figure since then, she said.

Another Zerona patient, Annie Bonvouloir, 53, of Nederland, Colo., who heard about the procedure on “The Doctors,” was less successful.

Hoping to reduce her thighs and midsection without the risks and inconvenience of liposuction, she paid $2,300 for six treatments from a chiropractor in the Denver area. Even though she continued to diet and work out, she had no change in her thighs, belly and hips. Her doctor offered her three more sessions at no cost. Still, no change.

Since most aesthetic medicine is elective, and not covered by insurance, marketing plays a major role in capturing the minds and wallets of consumers. The concern is that promoting innovations for indications that the Food and Drug Administration hasn’t approved will fuel patient expectations that clinical data may not substantiate.

Zeltiq Aesthetics, based in Pleasanton, Calif., is a cautious wallflower that aims to get the data behind its device approved by the F.D.A. before it makes too rowdy an entrance to the party. Its slogan is “More Science. Less Fat.”

Meanwhile, Erchonia Medical, based in McKinney, Tex., has aggressively marketed its Zerona laser as “the first non-invasive body contouring procedure to effectively remove excess fat” even though it has yet to receive F.D.A. clearance to promote this use. (In general, the F.D.A. must sanction a medical device for a specific use before a company can market that use. But doctors are free to use devices off label. )

Nonetheless, a brochure for Zerona states patients can collectively “lose up to 9 inches without the pain or down time of surgery.” Nationwide, medical spas, chiropractors, cosmetic surgeons, plastic surgeons and dermatologists now offer Zerona for $1,700 to $3,800 for six sessions. Part of the reason the device has made inroads during these strapped times is that doctors don’t buy it outright, but pay per use.

So how is Zerona supposed to work? The low-level laser causes “fat to seep out of a cell, almost like a balloon being struck by a needle,” said Ryan Maloney, medical director for Erchonia Medical. The fat enters the lymphatic system, and is eventually used as energy, Dr. Maloney said.

Zeltiq uses controlled cooling to target and eliminate fat cells, a process called selective cryolipolysis. Skin isn’t damaged, but subcutaneous fat, which is more sensitive to targeted cold, begins a two-month death march soon after exposure to Zeltiq.

Doctors on the advisory board for Zeltiq Aesthetics have put the word out about it on television news segments. But at this stage, the company itself has been careful not to promote its device directly to consumers since its F.D.A. clearances for, say, pain reduction during dermatologic treatments don’t encompass fat reduction. Gordie Nye, the chief executive, sent an e-mail message declining to be interviewed for this article.

The company has clinical data that has been submitted to the F.D.A. for approval, according to a few doctors who were principal investigators. Data relayed at a meeting of the American Society of Dermatologic Surgery showed a 22 percent reduction of the fat layer as measured by ultrasound.

Erchonia Medical has published the results of its clinical trial in Lasers in Surgery and Medicine. Thirty-five patients in the treatment group lost an average of 3.5 inches total in hips, thighs and their midsection according to the company’s clinical trial. The company has promoted Zerona as “a new body-sculpting procedure designed to remove fat and contour the body without invasive surgery.” But the F.D.A. has not sanctioned marketing this use. It has cleared the Zerona laser for pain reduction 24 hours after breast augmentation or as a way to decrease the pain associated with recovering from liposuction.

In general, Karen Riley, a spokeswoman for the F.D.A., said “it is considered off-label promotion if you are marketing to the public a use that has not been cleared.” Steven Shanks, the president of Erchonia Medical, said, “Since we use the exact same power for liposuction and breast augmentation, we self-certified the device.” He said that in January 2009, the company had applied for a 510K clearance — which is based on the notion that an older device is substantially equivalent to a new one — and had yet to receive it. (Such a delay is atypical, Ms. Riley said, adding, “most 510Ks are cleared within six months.”)