The Federal Trade Commission on Tuesday sent warnings letter to 10 companies that allegedly overstated the power of their products to combat coronavirus, COVID-19. It was not the first time the U.S. agency has had to notify marketers about tactics that could cross the line. The FTC and Food and Drug Administration had sent 26 similar letters in the past two months, targeting companies that make unrealistic medical claims. 

The regulators have been checking Instagram hashtags and Amazon product descriptions to hunt for potentially misleading marketers that are trying to capitalize on the coronavirus pandemic. To date, they have targeted CBD sellers, homeopathy remedies, herbal supplement providers and other medical-based marketers, including televangelist Jim Bakker. In the latest round of warnings, the FTC targeted a handful of companies running Facebook and Instagram accounts and Amazon sellers.  

In its letters, the FTC named products and services like Vitamin C injections, face cleansers, and wellness devices that resonate frequencies that kill coronavirus.  

The agency said it contacted Resurgence Wellness, based in Texas, accusing the company of marketing Vitamin C treatments by claiming they stave off coronavirus. The FTC said it found Instagram posts from the company that used hashtags like "Covid19" and "coronavirustreatment." Resurgence Wellness also runs a Facebook page that has links to its website to buy the intravenous Vitamin C dose, the FTC said in its letter to the company. 

"Any coronavirus related prevention or treatment claims regarding such [products] are not supported by competent and reliable scientific evidence," the FTC wrote. "You must immediately cease making all such claims." 

Federal regulators and law enforcement have been on the lookout for frauds that are proliferating during the pandemic, especially online, where there has been a flood of misinformation and predatory marketing. Ad Age reported this week on a company called Novads OU, registered to an address in Estonia, which has been selling a face mask called OxyBreath Pro. The U.K.'s Advertising Standards Authority has said Novads OU made misleading claims about the effectiveness of the product. 

The face mask marketer was able to use Facebook, Google, Bing and Snapchat to advertise despite each having policies for banning such ads. The platforms have been upgrading their detection capabilities and refining their policies to try to weed out marketing opportunists.  

On Tuesday, the FTC said it went after several companies with Facebook pages that were promoting Vitamin C treatments, including Rocky Mountain IV Medics, MedQuick Labs and Pura Thrive. 

The FTC did not say the companies ran ads on Facebook or Instagram. The agency just pointed to their pages on the social network. 

The FTC also named a Florida-based company called Face Vital, which sells a face-cleansing device. The FTC said Face Vital marketed a silicone face brush to "ramp up" beauty and "fight off corona." 

Another product that was targeted was an air filter by a company called Light Air, which the FTC said promoted an air purification system that "prevents the spread of air-borne viruses." 

"We have determined that you are unlawfully advertising that certain products treat or prevent Coronavirus Disease 2019," the agency wrote.