The first rule of sponsored content: You have to tell people it was paid for.

Today, the Federal Trade Commission publicly admonished over a dozen health influencers for publishing videos on TikTok and Instagram about sugar and the artificial sweetener aspartame without disclosing that the posts were paid for by the American Beverage Association and The Canadian Sugar Institute.

The FTC says this makes each of them potentially on the hook for fines over $50,000 if they continue posting without disclosures. Samuel Levine, who heads the FTC’s Bureau of Consumer Protection, called it “irresponsible for any trade group to hire influencers to tout its members’ product” without making sure content creators are clear about the deal. The FTC identified instances of “inconspicuous placement, ambiguous language, or the failure to clearly identify the sponsor of the posts” in its letters.

The idea that aspartame actually poses any cancer risk may be dubious, but that doesn’t have any bearing on the fact that two companies with a vested interest in these industries are paying heavily followed creators to “debunk” claims online.

In its warning to influencer Adam Pecoraro, the FTC quoted one video wherein the Instagram and TikTok influencer claimed that the International Agency for Research on Cancer (IARC) “should be almost completely disregarded.” He also said that IARC had “leaked” to Reuters that it was going to identify aspartame as a class 2B carcinogen. The FTC said Pecoraro’s use of the “paid promotion” tag in TikTok isn’t enough. It wrote in the letter that he “made endorsements audibly, so the disclosures should also have been audible.”

The FTC’s Guides for endorsements and testimonials dictates that content creators’ relationships with their sponsors should be “clearly and conspicuously” disclosed. It gave each of the letter recipients 15 days to explain how they’re planning to do that in the future.