WASHINGTON (CNN) -- While a drug maker is promising to introduce a new cholesterol-blocking margarine to the United States in January, federal regulators cast doubt on that timetable.

McNeil Consumer Products said it expects to launch Benecol in the United States in January of 1999, but the Food and Drug Administration said it has received no information about the product and has not been requested to consider approving it.

Since Benecol contains a food additive, the active ingredient which is said to block cholesterol, it must be approved by the FDA before it can be sold in the United States.

To be approved, a product must undergo rigorous testing, which could potentially take years.

The margarine is available in Finland, and apparently the pharmaceutical company McNeil Consumer Products, has bought the right to market it in the United States.

The active ingredient in the margarine is sitostanol, a natural plant alcohol from pine trees that inhibits the absorption of LDL or the so-called "bad" cholesterol into the blood stream.

Since sitostanol is an additive, it could potentially be added to any food. A spokesperson for McNeil said it is likely the company will add it to other foods such as salad dressings.

If a product contains an additive such as this one, or makes a health claim, it must have FDA approval before it can be available to consumers.

There is a gray area, however. If a product claims to be a "dietary supplement," it does not need FDA approval, because there are no laws governing dietary supplements.

McNeil said they can not reveal how they plan to market the product at this time.

National Association of Margarine Manufacturers spokeswoman Sue Taylor warned that there could be some negative side effects to this additive.

Anytime you block absorption in the intestines, you will have some kind of gastrointestinal effect, such as diarrhea and stomach aches, Taylor said.

Taylor said it was not a low-fat margarine. People would still be consuming fat, but it will not contribute to cholesterol levels, she said.