Weight-loss supplements that promise fast results are far from new—the first diet pills were sold in the late 1800s—but just as those over-the-counter medications proved worthless, today’s batch doesn’t seem much better, according to a new study in the journal Diabetes, Obesity, and Metabolism.
Researchers reviewed 54 randomized, placebo-controlled trials of herbal and dietary supplements, with over 4,000 participants represented. These included:
- Green tea
- White kidney bean
- Yerba mate
- Licorice root
- Garcinia Cambogia
- East Indian globe thistle
Only white kidney bean supplements showed a statistically significant amount of weight loss compared to a placebo, but even with this one, the difference was so modes (about three pounds) that it’s not worth recommending as an option, says lead researcher Erica Bessell, PhD, of the Boden Collaboration for Obesity, Nutrition, Exercise and Eating Disorders at the University of Sydney in Australia.
That’s particularly true given that people fluctuate in weight throughout the day, especially on weekends, one 2014 study found. The average is about five pounds of fluctuation, so “losing” three pounds with a supplement is not very notable, Bessell says.
“Unlike pharmaceutical drugs, which require rigorous testing and clinical evidence that demonstrates their safety and effectiveness, over-the-counter herbal and dietary supplements are not required to prove they work,” she notes. “In our research, it appeared that most supplements seem safe based on short-term usage, but they don’t provide any meaningful weight loss.”
In another analysis, the researchers looked at 67 other randomized trials representing about 5,000 participants that involved non-herbal options such as conjugated linoleic acid, chitosan, and glucomannan—these are complex sugars and soluble fiber that manufacturers claim will promote feelings of fullness and even block the absorption of fat or carbohydrates.
Like the white kidney bean supplement, these all showed some weight loss in comparison to the placebo, but not enough to be recommended to those trying to lose extra pounds.
“These supplements might seem like a quick-fix solution to weight problems,” says Bessell, and that can be especially true with bold promises and plenty of marketing, including supposed “before and after” photos of satisfied customers. But, she adds, there’s little data about long-term effectiveness.
That means you might lose a bit of weight—if you’re lucky—but in terms of significant weight loss that stays gone? There’s simply not enough evidence to back up those claims.
For more, be sure to check out Surprising Side Effects of Taking Vitamin D Supplements, Says Science.