Google “diet supplements” and you’ll get about 13 million search results, most from companies selling products that promise to cure your weight problem—in as little as a week. Their proprietary formulas, which can cost $40 a bottle and up, are often touted as all natural, healthy and proven to work with no side effects.
But weight loss is neither quick nor easy. Nothing melts fat away, and certain pills can have serious side effects. Dietary supplements do not have to be tested for safety or effectiveness, nor do they have to list warnings or contraindications. And the Food and Drug Administration (FDA) can pull them from the market only after there’s proven evidence of harm.
That’s what happened with ephedra, which the FDA finally banned in 2004—but only after serious problems and even deaths were reported. Since then, ephedra-like substances, including synephrine (in bitter orange) and dimethylamylamine (sometimes listed as geranium oil), have taken its place and may not be any safer.
More cause for alarm: Some weight loss products have been found to contain undeclared pharmaceuticals, which can be harmful if not used properly. In recent years, the FDA has warned about dozens of diet supplements, many from China, that were tainted with drugs, including amphetamine-like chemicals, tranquilizers, antidepressants, prescription diuretics and anti-seizure medications. Keep in mind that if a diet product does work, it’s likely to have other effects that may not be so desirable. Some ingredients (such as chaste tree, daidzen and dong quai) can affect levels of some hormones. And diet aids, even if natural, may interact with medications. Our What's in Your Diet Pills? slideshow will give you the rundown on some common ingredients in diet aids.
Bottom line: At best, there’s slim evidence for a couple of common ingredients in diet supplements. Don’t expect such supplements to help you lose much weight. Even if some do cause you to lose a few pounds, none are proven to sustain weight loss, which is key.