New Delhi, July 23 -- WASHINGTON - The compound did not come with a prescription or a pharmacist's consultation. It arrived in a plain package, ordered from an overseas website by a Texas man who had watched dozens of social media videos praising BPC-157 as a recovery agent for joint pain. When his knee did not improve after several weeks of self-administered injections, he stopped. Nobody had told him the peptide had not been tested for human use in any formal clinical setting, or that US regulators had spent years trying to determine whether it was safe at all.

That gap between internet enthusiasm and scientific evidence sits at the center of a two-day hearing convening this week at the US Food and Drug Administration. The agency's Pha...