ConsumerLab.com tested 13 supplements and found that 11 did contain the amount of resveratrol claimed on the label. But compared with the amount given to mice, the supplements contained relatively little resveratrol.
Sales of red wine supplements have grown by more than 300 percent during the past year. Their popularity stems from several research studies published last year which found that mice that were fed resveratrol, a component of red wine grapes, lived longer.
Filmmaker and writer Daedalus Howell is intrigued by the promise of resveratrol. When he first heard about the research, he offered to be a test subject in a human study to see if the longevity effect found in mice holds up in people.
"I think if I can make myself available to help humanity," says Howell with a laugh, "by all means I'd do it!"
So far, researchers have not taken him up on his offer. And it turns out, there's very little known about how the red wine compound acts in the human body. But, this hasn't stopped people from buying red wine supplements.
New Supplement Analysis
ConsumerLab.com tested 13 resveratrol products. It found that compared to the amount given to mice, the supplements contained relatively little resveratrol.
One product tested, called Revatrol, contained 400 milligrams of a whole red wine grape complex, with an unspecified amount of resveratrol, according to its label.
"Clearly a consumer can be misled," says Tod Cooperman, president of ConsumerLab.com.
He says consumers go out to buy a particular ingredient.
"In this case, they're looking for resveratrol," says Cooperman and they find a product called Revatrol. "They really have no idea that the amount of active ingredient can be just a miniscule amount of the total."
With Revatrol, the lab test found only 2.2 milligrams of resveratrol per caplet; less than 1 percent of the total blend. Since the quantity of resveratrol was not listed, it is an accurate label.
"There's nothing misleading about our labeling or advertising," says, James DiGeorgia, president of Renaissance Health Publishing, which distributes Revatrol. DiGeorgia says he has released a new version of Revatrol this year, which contains 100 mg of resveratrol. "We changed the formula and improved the formula," says DiGeorgia.
Failing the Test
ConsumerLab.com found two products that contained much less resveratrol than was stated on the label. One product, Life Extension Resveratrol Caps (20 mg per capsule), contained only 26.5 percent of claimed resveratrol. The Fort Lauderdale, Fla., company that distributes the supplement says it's looking into the results.
Another product called Resvert, now distributed under the name Supplement Spot, contained only 58.2 percent of claimed resveratrol.
Safe, but Little Regulation
Since there's no official recommended dose for resveratrol and no government regulation of the supplement, distributors are free to sell and say just about anything about their products. The Food and Drug Administration doesn't step in unless there are reports of harm.
Dr. William Gruss, a practicing physician and a paid spokesman for Revatrol supplements, says he thinks the red wine capsules are safe. He's noticed benefits since he began taking the caplets.
"I've felt subtlety more energy, I felt more endurance and actually I've even lost weight," says Gruss.
Buy with Caution
Personal testimonies are not enough to convince Dr. Brent Bauer, who specializes in alternative and complementary medicine at the Mayo Clinic.
There are intriguing findings in the animal studies of resveratrol, showing the compound has antioxidant and anti-inflammatory properties. "The challenge is, of course, that we don't have any good clinical trials — in other words, human trials," Bauer says.
A toxicity review under way by the National Institute of Environmental Health Sciences won't be finished for a few years.
Researchers say one possible concern is that resveratrol may affect estrogen activity, which could be an issue for women of child-bearing age.
With all the unknowns, writer and wine-lover Daedalus Howell says he'll stick with the time-tested way of imbibing grape extract.
"Wine drinking goes back eons and it's certainly a romantic endeavor," Howell says. He asks, "Have you ever showed up at someone's house with a supplement and flowers?"