FDA says compounded GLP-1s with added vitamins are still copies of approved drugs

In a September 18, 2026 warning letter to a large Houston compounding pharmacy, the FDA said its tirzepatide with niacinamide and semaglutide with cyanocobalamin (vitamin B12) injections were essentially copies of FDA-approved drugs. The agency said the volume produced suggested the claimed differences from the approved products were pretextual, and it criticized templated prescription justifications. Under section 503A, pharmacies may not regularly compound copies of approved drugs unless a prescriber documents a significant clinical difference for the individual patient.