Some compounded versions caused serious side effects, including nausea, vomiting and hospitalizations from dosing errors
The pen is still good
The purchaser should maintain restricted access, receipt records, storage logs, and clear internal labeling
For broader supplier-quality checks, Pharmints guide on GMP-certified API manufacturers explains how buyers can review certification scope, inspection history, DMF or dossier claims, COA availability and supplier transparency before approving a source
Fish Shellfish Immunol 49:427435 Stec DE, Gordon DM, Hipp JA, Hong S, Mitchell ZL, Franco NR et al (2019) Loss of hepatic PPAR promotes inflammation and serum hyperlipidemia in diet-induced obesity
Doctors also dont check B12 levels during routine blood work as most of the time its stored in the liver with years of stock, or its symptoms may get confused with the symptoms of other conditions