SAN DIEGO -- It's the most popular artificial sweetener currently on the market, but competitors and health care professionals say there could be a sour side to Splenda.

Splenda is the brand name for the artificial sweetener Sucralose. While it is made from sugar cane, it is unlike sugar because it is processed with chlorine, NBC 7/39 reported. The unique chemical process makes it possible for Splenda to pass through the body unabsorbed, according to doctors.

"(It's) not absorbed -- (it) passes right through," said Dr. Ken Fujioka, M.D., of Scripps Nutrition & Metabolic Research Center. "What's interesting is you don't get gastrointestinal side effects. You rarely ever see that."

"The fact that it passes through the intestine unabsorbed means you have to be careful of how much you put in at this end or you won't be too happy with what's going on at the other end," said Dr. David Katz, of the Yale School of Public Health.

While Spenda was made popular by the South Beach diet, it is not clear that the product actually helps people lose weight. Some research shows that it could do the opposite.

In a study published in the International Journal of Obesity, laboratory animals fed no-calorie artificial sweeteners showed signs of confused appetite. The animals became incapable of regulating their calorie intake, Katz said.

The makers of Splenda also criticize the weight-loss research, saying "a significant body of science does not support these findings, including studies in people."

The battle over Splenda goes beyond weight control, however. Lawsuits filed by two competing artificial sweetener companies and the sugar association call Splenda's advertising false, because the company implies the product is "natural."

"We think that the chemical process is such that there is nothing left of the essence of the sugar at the end of the process," said Jim Murphy, of the Sugar Association Attorney.

Splenda's makers say they don't claim their sweetener is natural. It has filed a counter lawsuit accusing its competitors of a "false and malicious smear campaign" designed to frighten consumers.

"Splenda has an unparalleled safety profile; it has been approved in every country that we've ever submitted it for approval," said Colin Watts, President of McNeil Nutritionals. "It carries no safety or warning label whatsoever."