CBS News lab-tested vials sold as retatrutide: a corner-store vial had no peptide and 13 bacteria colonies

What happened

CBS News bought three vials sold as retatrutide, the experimental weight-loss peptide Eli Lilly is still testing in clinical trials. Two came from websites that promised a health check or a doctor's review, and both arrived without anyone speaking to the buyer. The third was a $90 vial from a corner store in Brooklyn, labeled research use only and not for human consumption.

CBS had all three tested at the University of Iowa and published the results on October 21, 2026, in a CBS Mornings investigation.

What the lab found

Research scientist Jason Galpin found that both vials bought online were consistent with a basic retatrutide standard he made. CBS notes that this standard is not the same as the drug Lilly is studying in its trials.

The corner-store vial did not appear to contain a peptide at all. Galpin found phenylacetic acid, which he described as a filler and which is common in fragrances and lip balms. A second test, by Carl Ross at the university's Center for Biocatalysis and Bioprocessing, found 13 colonies of bacteria in it. Ross said injecting material contaminated with bacteria could cause an infection.

What it means for you

This was a small test: three vials, and the report gives no purity, dose or sterility numbers for the two that matched. A match to a basic standard says the peptide is there; it does not say how much, how pure, or whether the vial is sterile.

If you run reta, ask for third party test results on your batch, and buy from a source you know. If you get signs of infection where you injected, see a doctor now.

The fine print

Retatrutide is not approved by the FDA. A Yale physician interviewed by CBS, Dr. Reshma Ramachandran, said people using it are acting as test subjects because the drug has not yet been shown safe and effective. Eli Lilly told CBS that a single test is a snapshot and does not show the next vial will be safe.