A novel, widespread impurity in mass-compounded tirzepatide/b12 products: patient safety implications

Despite the presence of this impurity, these products continue to be mass marketed as 'personalized' treatments. Our findings underscore the importance of testing and FDA approval before new drugs are marketed and highlight potential risks for patients associated with untested combinations. A novel impurity, present at substantial levels in compounded tirzepatide/B12 products, highlights risks inherent in marketing complex therapies outside the drug‑approval framework. Although clinical effects of this impurity are unknown, the identification of a widespread impurity adds to the existing quality concerns presented by compounded tirzepatide.