Lilly’s B12 ‘bombshell’ – or is it?

Eli Lilly dropped a statement on Thursday claiming its testing of compounded tirzepatide + vitamin B12 uncovered a significant impurity resulting from a chemical reaction between the two, and warning patients they may be using a potentially dangerous product with unknown risks.

It’s a serious claim, but as APC’s CEO noted in response, one with a lot of heat and not much light.

For starters, Lilly didn’t say where it got its samples from. That matters – a lot. Both Lilly and Novo have a habit of announcing alarming test results from “compounded GLP-1s” without disclosing whether those staples came from state-licensed compounding pharmacies or unlicensed med spas, bogus websites, or offshore resources. Those are very different things, and conflating them – intentionally or not – is a disservice to patients and policymakers.

Lilly also doesn't answer some pretty basic questions on sample handling: How were they obtained? How old were they? Were they properly stored? Was the seal intact when sampled?

These answers matter when talking about the presence of impurities or other contaminations.

Additionally, a lack of data also raises other questions for the Lilly statement. All drugs, even FDA-approved ones, are allowed a certain level of impurities that do not negatively affect the patient. What is the “impurity” Lilly discovered, how did they determine its "significant levels,” and how does that compare to FDA standards?

B12 is a remarkably well-studied and benign compound, with about four years of compounding use in prescriber-authorized tirzepatide + B12, and there’s yet to be any alarming trend of adverse events. If there were a serious safety signal, you’d expect to see it by now, yet Lilly says they’ve “uncovered” significant interaction that puts patients at risk.

If that’s the case, Brunner said APC would take that extremely seriously, and we’d expect the FDA and state boards of pharmacy to move quickly. But patient safety deserves evidence, not insinuation, he added. Right now, Lilly’s statement raises more questions than it answers – and who's to know when those answers will come – if ever.