Senators Urge FDA to Crack Down on ‘Research Use Only’ Drugs

Sen. Jim Banks (R-IN) is leading a group of senators urging FDA to ramp up enforcement against online vendors using “for research use only” labeling to market unapproved drugs and active pharmaceutical ingredients (APIs) to consumers, citing growing concerns about counterfeit versions of Eli Lilly’s investigational weight-loss drug retatrutide.

In a 10/14 letter to acting FDA commissioner Kyle Diamantas, the lawmakers warned that vendors are exploiting research-use labeling to circumvent FDA oversight and sell potentially dangerous products intended for human consumption.

The senators pointed to widespread online sales of retatrutide, which has not received FDA approval. According to the letter, America's Poison Centers reported a 265% increase in poisonings associated with illicit retatrutide during the first four months of 2026 compared with the final four months of 2025.

The lawmakers said FDA has issued Warning Letters to at least seven companies marketing retatrutide as research-use-only while simultaneously promoting it for obesity, diabetes and other human uses. More than a dozen additional companies have received warnings involving unapproved retatrutide products and misleading marketing claims.

The senators also raised concerns about foreign supply chains, particularly APIs sourced from unregulated Chinese manufacturers, and shipments allegedly concealed through falsified documentation and mislabeling.

“We commend the FDA’s enforcement efforts, but we urge you to work more closely with U.S. Customs & Border Protection and other law enforcement agencies to take these illicit drugs off the market and hold the companies selling them accountable,” the lawmakers wrote.

They requested an FDA briefing addressing the extent of research-use-only labeling abuses, coordination with customs and law enforcement agencies, and the agency's capacity to investigate and take enforcement action against illicit drug and API vendors.