What makes a requirement binding here
State law — fifty of them, plus territories, each with its own pharmacy practice act and its own board of pharmacy. This is a jurisdiction on the axis because it behaves like one: for a compounding pharmacy operating under section 503A of the Federal Food, Drug, and Cosmetic Act, the primary regulator is the state board, not FDA. The federal statute defines the exemption; the state licenses the pharmacy, inspects it and can close it.
Through a pharmacy licence issued by the board of the state where the pharmacy operates, and — the part most often missed — through a separate nonresident or out-of-state licence in each state the pharmacy ships into. Compounding standards enter state law by adoption by reference: USP General Chapters ⟨795⟩ for non-sterile, ⟨797⟩ for sterile and ⟨800⟩ for hazardous drugs became officially enforceable on 1 November 2023, and the large majority of state boards require compliance with ⟨797⟩ or incorporate it into state regulation — but the version adopted and the date enforcement begins vary by state.