The U.S. Food and Drug Administration (FDA) has said that dietary supplements should not be taken if they claim to replace steroids or prescription drugs.

The announcement came as the FDA investigated hundreds of supplements that contained illegal or unlisted ingredients, including anabolic steroids and diet drugs.

Hundreds of supplement lines have been seized by the agency, which published a number of guidelines for consumers.

It recommended that individuals avoid products that claim to naturally mimic prescription medications, like those that treat obesity or erectile dysfunction.

Any supplements that are labeled entirely in a foreign language should not be purchased or consumed, the FDA said, nor should “natural” steroids, cure-alls or supplements mass-marketed by email.

In the end, consumers are urged to stick to legally approved, healthy supplements that contain no additives or prescription compounds.

These include garlic, which has natural antiseptic and antifungal properties, and saw palmetto, which may reduce prostate inflammation and contribute to urinary tract health.