(NBC News) The Food and Drug Administration is warning consumers to stay away from dietary supplements that claim to promote sexual enhancement, weight loss or body building because they may contain hidden — and potentially dangerous — ingredients.

Such products are sold without a prescription on various websites, including Amazon, and possibly in some retail stores, according the FDA.

But often, consumers aren’t getting what they paid for.

“Very often, the supplement pills don’t even have in them what they say on the bottle,” Dr. Daniel Shoskes, a urologist at the Cleveland Clinic, said.

Worse, they could be spiked with pharmaceuticals that can have dangerous interactions with other medications, he added.

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