Federal officials plan to send warning letters to companies marketing products with 7-OH, part of effort to fight America's opioid addiction problem.

Federal health officials are calling for urgent action against a powerful, unregulated substance being sold in gas stations, vape shops, and convenience stores across the country.

The FDA recommendation follows a detailed scientific review and is part of broader efforts to address concerns about the rise of 7-OH opioid products. Currently, 7-OH has no FDA-approved drug uses and is not legally permitted in dietary supplements or conventional foods.