READ THIS NEXT: If You See These 2 Words on a Supplement Bottle, Don’t Take It, Experts Warn. Outside of food and drug products, the FDA is also responsible for regulating dietary supplements. But unlike the former, the agency does not approve dietary supplement products before they are sold to public consumers, according to the U.S. Department of Agriculture (USDA). Instead, manufacturers and distributors are “responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all the requirements regulations.” If they don’t, the FDA can then take action after the fact. This means you could run the risk of buying supplements that contain unsafe ingredients. If a supplement is considered unsafe by the FDA, it is usually adulterated. Under the Dietary Supplement Health and Education Act (DSHEA) of 1994, a dietary supplement is deemed as adulterated if it includes ingredients or additives that could put consumers’ health or safety at risk. The FDA posted a new alert on May 9, notifying consumers that they had issued warning letters to multiple companies selling adulterated dietary supplements. The letters were sent to 10 different companies: Advanced Nutritional Supplements, LLC; Exclusive Nutrition Products, LLC (Black Dragon Labs); Assault Labs; IronMag Labs; Killer Labz (Performax Labs Inc); Complete Nutrition LLC; MaxMuscle; New York Nutrition Company (American Metabolix); Nutritional Sales and Customer Service LLC; and Steel Supplements, Inc. “The FDA has requested responses from the companies within 15 working days stating how they will address these issues, or providing their reasoning and supporting information as to why they think the products are not in violation of the law,” the agency said. “Failure to adequately address this matter may result in legal action, including product seizure and/or injunction.” RELATED: For more up-to-date information, sign up for our daily newsletter. These companies are selling supplements with concerning ingredients, according to the FDA. The agency said that some of the supplements contain new dietary ingredients (NDIs) that have not been properly vetted by the FDA. As mandated by the Federal Food, Drug, and Cosmetic (FD&C) Act, manufacturers who wish to use NDIs in their dietary supplements must notify the FDA about these ingredients and include information that concludes the new ingredients are safe to use.ae0fcc31ae342fd3a1346ebb1f342fcb Some of the supplements also contain unsafe food additives, according to the agency. “The dietary supplements sold by the companies listed above contain one or more of the following ingredients: 5-alpha-hydroxy-laxogenin, higenamine, higenamine HCl, hordenine, hordenine HCl, and octopamine,” the FDA warned. “The agency has previously expressed concern about several of these ingredients for reasons including, for example, the potential adverse effects of higenamine on the cardiovascular system.” The FDA said that some of the companies are also selling dietary supplements that are unapproved drugs. Under the FD&C Act, “products intended to diagnose, cure, treat, mitigate, or prevent disease are drugs and are subject to the requirements that apply to drugs, even if they are labeled as dietary supplements, and generally require pre-approval from the FDA.” None of the companies have gained approval from the FDA, and the agency said it has not evaluated whether these unapproved products are effective for their intended use, what their proper dosage should be, how they might interact with actual FDA-approved drugs and substances, or whether they could have dangerous side effects or other safety concerns. “These products could potentially harm consumers,” the FDA warned. READ THIS NEXT: If You’re Taking This Popular Supplement, It Could Be Causing Nightmares.