A US advisory panel has urged regulators to approve the use of an injection of collagen and tiny plastic beads as a long-term fix for wrinkles.

Artecoll, made by privately held Artes Medical, could provide competition to the Botox and collagen shots that are popular with Americans craving a younger look.

Results from those injections last up to about six months. Artecoll, by contrast, is a permanent implant for ironing out wrinkles long-term, its maker said.

A study presented to a US Food and Drug Administration (FDA) advisory panel compared results from collagen and Artecoll six months after the injections.

"The data is pretty convincing it's effective," said Dr. Michael Miller, a panel member and plastic surgeon from the University of Texas M.D. Anderson Cancer Center.

The panel voted 4-1 to recommend Artecoll's approval, giving the product a major boost toward the market, since the FDA usually follows its panels' advice.

Panel members said it was important to make sure physicians were skilled in injecting the permanent material. They also said patients should be informed of potential risks, which can include lumps on the face.

The panel also said it favored post-marketing studies of patients at least five years after patients received injections, and said the product should not be approved for lip augmentation.

Artecoll contains tiny spheres of polymethylmethacrylate, or PMMA for short, suspended in bovine collagen. PMMA is a polymer that has been used for more than 50 years in medical devices ranging from contact lenses to bone implants.

The PMMA spheres, about the thickness of a human hair, settle in wrinkles as the bovine collagen gradually absorbs into the body, the maker said. Then, the spheres stimulate the body's own collagen to encapsulate them.

A study found Artecoll patients had less severe lines between the nose and lips than collagen patients six months after treatment, as judged by researchers who reviewed patient photos. The study did not show a statistically meaningful difference between the two treatments in other areas of the face at the same time point, FDA reviewers said.

For some patients in Europe, where the product has been available for years, Artecoll's effects have lasted up to 10 years, company officials said.

FDA reviewer Binita Ashar said 16.3 per cent of patients treated with Artecoll experienced an "adverse event," such as lumping or redness. Thirteen percent of collagen patients had adverse events. More Artecoll patients had lumpiness that persisted beyond six months, Ashar said.

Artes Medical said lumps were treatable with cortisone shots. "I have never heard of any long-lasting disfigurement after Artecoll injections," said Dr. Gottfried Lemperle, Artecoll's inventor and the chief scientific officer for Artes Medical.

But Diana Zuckerman, president of the National Center for Policy Research for Women and Families, said the FDA should require longer studies before approving Artecoll.

"If this product is approved, tens of thousands of women--probably even more--will have this product permanently injected in their faces. And yet, we really have no idea what will happen to them after two or three or four or 10 years," she told the panel.

Company officials said they expect a final decision from the FDA in the coming months. If approved, Artecoll would be sold in the United States under the brand name Artefill.

Artes Medical is based in San Diego. Irvine, California-based Allergan Inc. makes Botox, which smoothes wrinkles by paralyzing the muscles that cause facial lines. Inamed Corp. of Santa Barbara, California, sells collagen under the brand names Zyderm and Zyplast.