Dr. Jame Heskett, a New York-based M.D. dedicated to helping women maintain their youthful glow, remembers the first time she tried the fat-reducing treatment involving carbon dioxide injections into the skin that has become somewhat controversial.

"I've always had kind of like chubby thighs - just slightly out of proportion to the rest of my body," Heskett, founder of The Well Path medical spa in New York, told HNGN.

So she administered a shot of CO2, the same gas found in air and fire extinguishers, into her right thigh. It destroyed her fat cells and opened her blood vessels, increasing circulation while speeding up her body's healing process. She was amazed by the results.

"My right thigh was clearly like an inch smaller than my left thigh!" Heskett said.

The revolutionary procedure, called carboxytherapy, originated in France and arrived in the U.S. in the early '00s. A decade later, Heskett and other doctors say carboxytherapy has blossomed into a highly coveted fat-busting, cellulite-reducing cure-all treatment. This success is owed to the fact that more and more people are shifting toward noninvasive cosmetic injections.

"A lot of folks are asking for it by name," said Dr. Lisa Zdinak, one of the first physicians to introduce carboxytherapy to the U.S. "I have people lined up at the gas tank."

"Gas tank" is a good term to use since it's how carboxytherapy is performed - a tank full of medical grade CO2 is hooked up to a tube, which is hooked up to a needle that's inserted beneath the skin. A doctor or nurse regulates how much gas is pumped into the body. It's not painful, but "tingly," according to Zdinak, who has used carboxytherapy on herself for years.

Once underneath the skin's surface, the gas causes a slight disruption in the red blood cells due to the sudden overflow of carbon dioxide, which the body naturally produces as cellular waste.

The blood vessels expand and increase circulation to the oxygen-deprived area while the gas is eliminated, giving the skin a youthful appearance.

"It's a natural response of the body to the carbon dioxide," said Heskett, who has performed carboxytherapy for 15 years. "The disruption allows the body to sort of super repair the area."

If stretch marks are the target, the carbon dioxide helps increase blood flow to activate collagen production and decrease the marks. Fat cells are also destroyed by CO2.

The process sounds draconian, but Zdinak says it's quick, there are no risks and the results are "brilliant," especially for treating dark under eye circles, back fat, cellulite, wrinkles and hair loss.

"Carboxytherapy is what people do if they are looking for something completely natural," Zdinak said.

At New York's Precision Aesthetics skin care spa, where Zdinak is the chief surgeon and medical director, 10 to 20 procedures are performed each week. Clients from France, Argentina and the U.K. flock to her for weekly treatments; beauty pageant contestants pop by for a quick fix and brides-to-be get their calves injected before their weddings. Men come too - from former body builders to grocery store owners, Zdinak said.

Prices range from $150 to up to $1,000 packages depending on the clinic.

Without Zdinak, carboxytherapy probably would not have arrived in the U.S. at all. The treatment was discovered back in the 1930s in France when doctors realized that water rich in carbon dioxide helped treat ulcers and cardiovascular ailments.

"People in Brazil kind of caught wind and the first thing they do in Brazil is ask 'How can we use this for beauty purposes?'" Zdinak said.

After hearing about carboxytherapy from a colleague in Rio, she did everything to find out more about the strange therapy, including using herself as a guinea pig. Zdinak first tried it on her abdomen. She didn't like it.

"It felt to me like a curling iron burn," she said. Now, the therapy has been improved by pre-heating the gas to body temperature.

But even with the treatment being perfected and customers living lives free of dark eye circles and stretchmarks, carboxytherapy has acquired a reputation as potentially unsafe and risky due to a lack of research.

It's not FDA approved, and although there are virtually no side effects, doctors are of course going to be hesitant to sing its praises.

"I don't know of any published, peer-reviewed scientific study that proves the treatment is safe or effective," said Dr. Anthony Youn, a member of the American Society for Aesthetic Plastic Surgery who's been in private practice for 11 years.

"In my opinion, until this is done, this can be considered experimenting on patients."

Jacqueline Bermudez, of Miami, also cringed at the idea of CO2 injections.

"I don't even believe in Botox because I don't even think it's good for you," the 48-year-old Columbian native told HNGN. She said she's scared to put "that stuff" in her body.

"Now you feel beautiful, but what is it going to be in 10 years?"

There is a possible risk of bleeding, bruising, infection and scarring with carboxytherapy, Youn said. There's also a risk of orbital emphysema, when skin surrounding the eye swells from gas trapped underneath, but Zdinak said that is "more of an annoyance than a danger."

In 2009, the Physicians Coalition for Injectable Safety issued a warning against the cosmetic procedure.

"Carboxytherapy for use around the eyes is especially dangerous," said Dr. Robert Weiss, of Baltimore. "It could potentially release gas bubbles into blood vessels causing blindness." But Zdinak said the real danger is getting the injections done by someone who doesn't know what they are doing instead of a trained expert.

Heskett contends carboxytherapy will probably never be FDA approved because the administration considers CO2 gas a drug, "and to get a drug through FDA approval costs millions and millions of dollars."

FDA approval or not, carboxytherapy remains one of the most requested treatments at her medical spa, about 90 percent of 6,000 clients to be exact.

"Over the years I have noticed a very slow but persistent increase in people looking for it," Heskett said. Summer is the "high season," where about 50 women are treated weekly.

Zdinak, who still uses carboxytherapy, says she can't wait to see how it can help people in ways that go beyond the desire to look younger.

 "I think it's a very exciting time right now," Zdinak said.