Overview
- Company testing found a previously unidentified impurity formed by a chemical reaction between tirzepatide and vitamin B12 in all ten compounded samples obtained in the U.S.
- Lilly says the impurity’s effects in humans are unknown and advises patients using tirzepatide–B12 products to consult their physicians.
- Additional problems reported in tested products included inconsistent potency, with some at 43% of the labeled dose, bacterial contamination, high endotoxin levels, and other impurities.
- Lilly notified the FDA and called for a nationwide recall of compounded tirzepatide mixed with B12 or other untested additives, and no agency-ordered recall was reported in the coverage.
- The Alliance for Pharmacy Compounding questioned the sufficiency of Lilly’s public data as regulators and brand manufacturers escalate actions against mass-marketed compounded GLP-1 offerings.