On Tuesday, Sen. Richard Blumenthal (D-CT) wrote to the FTC requesting a federal investigation into the sale of “detox teas” on social media that are pervasively marketed by influencers on social media.

Online influencers like the Kardashians have long peddled weight loss teas to their millions of followers on Instagram and YouTube. Companies like Flat Tummy Co use brand ambassador programs that pay influencers to post a certain number of photos and stories to their Instagram accounts and other social media accounts to market their products. Teas are some of the most notable items, but other weight loss and appetite suppressors like shakes and lollipops are marketed in the same way as well.

“The dangers of these products, their widespread use, and deceptive marketing demand federal action,” Blumenthal said in a statement. “I call on the FTC ... to investigate the false and misleading marketing practices presented by the manufacturers of these teas and take appropriate enforcement action to protect unwitting consumers from harm,” Blumenthal wrote.

This wouldn’t be the first investigation into influencer marketing that the FTC has undertaken. In 2017, the FTC required influencers to explicitly notify their followers when posts are ads for brands by hash-tagging phrases like “ad” or “partner” in post descriptions. The FTC will often open investigations into deceptive and harmful business practices after members of Congress reach out or if products and scams make news headlines.

“Detox teas” have also been criticized for adverse health effects. Many of the teas use diuretics, laxatives, and a range of stimulants like caffeine in order to induce weight loss, according research by Consumer Reports. Due to these ingredients, the drinks can cause dehydration, diarrhea, and upset stomachs. If used for a long period of time, it can lead to potassium deficiencies in a consumer’s blood.

Blumenthal also encouraged the FTC to work alongside the FDA “to increase efforts to inform the public about the true harms of these teas, and to take steps to ensure that consumers are not duped by these dangerous, under-regulated products.”