But the makers of dietary supplements don't need to prove their products can do any of those things.
Jareem Gunter took a dietary supplement to improve his athletic performance. But he says it landed him in the hospital with liver failure.
"My eyes were jaundiced. My body was too, so my hands started turning yellow," Gunter said.
Gunter filed a lawsuit claiming the supplement contained an "illegal synthetic steroid." The suit has now been settled.
Consumer Reports' Nancy Metcalf says hazardous ingredients have been turning up frequently in three different types of supplements.
"The Food and Drug Administration has found synthetic steroids in supplements for body building and it has found prescription drugs in supplements marketed for weight loss and sexual enhancement," Metcalf said.
So Consumer Reports says beware of supplements for bodybuilding, weight loss, and sexual enhancement.
And even when the ingredients are known, Consumer Reports says some can be dangerous. Working with an independent research group, the Natural Medicines Comprehensive Database, Consumer Reports has identified 12 supplement ingredients you should avoid.
The FDA has warned about eight of them, some as early as 1993. Nevertheless Consumer Reports found all easily available on store shelves or online.
"These supplement ingredients have been linked by clinical research or case reports to serious side effects, including heart, liver, or kidney problems," Metcalf said.
Unlike prescription drugs, supplements aren't always required to list potential adverse effects on the label. "Without stronger oversight its buyer beware."
That's something Jareem Gunter learned the hard way.