The U.S. Federal Trade Commission slapped ten well-known Instagram influencers—including rapper Cardi B—with a warning for making “deceptive” endorsements on social media that failed to disclose their paid relationships with an advertiser.

On March 5, the nation’s consumer protection agency filed a formal complaint against Teami LLC, a tea company whose line of tea-based skincare products and “detox teas” allegedly helps users lose weight.

The FTC charged the company with misleading consumers by making claims "without reliable scientific evidence.” According to the complaint, among the “false or unsubstantiated” claims made by the company include suggestions that Teami’s products treat cancer, unclog arteries, decrease migraines, treat colds and flus and cause users to lose substantial weight.

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The agency also took action against Teami due to its “deceptive failure” to disclose that it was paying influencers to endorse the Teami products via social media.The FTC additionally said the company “engaged in their unlawful acts and practices repeatedly over a period of several years and continued their unlawful conduct for many months after they learned that the FTC was investigating them.”

In addition to its formal complaint against Teami, the FTC sent warning letters to ten influencers whom the agency alleges have made “deceptive” posts for failing to disclosure they were paid to promote Teami products.

Those influencers include singer Cardi B; singer, actress and television personality Adrienne Eliza Houghton; Actress and singer Alexa PenaVega; fitness model and author Brittany Renner; reality television personality Jenicka Lopez; social media fitness trainer Katya Elise Henry; model, actress and television host Leyla Milani-Khoshbin; and singer Jordin Sparks.

“When you endorse a product on social media, you should make obvious your financial or other relationship with the brand by clearly and conspicuously disclosing any material connection in the same post that you make the endorsement,” those warning letters read. “‘Clear and conspicuous’ means you should use unambiguous language and the disclosure must stand out. Consumers must be able to see the disclosure without having to click to expand additional text.”

No formal charges were brought against any of the influencers named in the FTC complaint.

Other influencers who’ve touted Teami’s products in the past include Kim Kardashian, Kylie Jenner, Demi Lovato and former Alaska Gov. Sarah Palin.

The FTC in late 2015 updated its transparency guidelines regarding how marketers should properly disclose native ad content. This includes prominent social media influencers, who must disclose the nature of their relationships with brands when promoting or endorsing products in exchange for compensation. The agency published an informal business guidance document on endorser endorsement in 2017.

“Social media is full of people peddling so-called detox teas, promising weight loss,” FTC Bureau of Consumer Protection director Andrew Smith said in a statement. “Companies need to back up health claims with credible science and ensure influencers prominently disclose that they’re getting paid to promote a product.”