Pharmacy compounding is the practice of preparing a customized medication for an individual patient, traditionally under a state-licensed 503A pharmacy or, at larger scale, under a 503B outsourcing facility registration. It exists for legitimate reasons — patient allergies to standard excipients, pediatric weight-based dosing, adjustments to dosage forms for patients who cannot swallow tablets, and continuing supply of discontinued formulations. It is also the regulatory category that absorbed the explosion of mass-produced GLP-1 'compounded' products during the 2023–2025 semaglutide and tirzepatide shortages.

503A and 503B, briefly

Section 503A of the Federal Food, Drug, and Cosmetic Act covers traditional pharmacy compounding: a licensed pharmacist prepares a medication in response to an individual patient prescription. Section 503B, added by the Drug Quality and Security Act of 2013, created a category of 'outsourcing facilities' that can compound larger quantities under stricter federal oversight, primarily to serve hospitals and clinics. Both categories were designed around the assumption that compounded drugs are not competing with approved commercial products at population scale.

Why a shortage changed the rules

When the FDA places a drug on its official shortage list, 503A and 503B compounders gain temporary latitude to prepare versions of that drug — the underlying reasoning being that patients who need the medication should not be denied it during a genuine supply disruption.^[1] Semaglutide entered the shortage list in 2022 and tirzepatide followed in 2023 as demand for GLP-1 receptor agonists outran the manufacturers' production ramp. In the gap that opened between prescribed demand and approved supply, a very large compounded-GLP-1 economy emerged — often operating through telehealth platforms and marketed to consumers alongside standard weight-management services.

The regulatory position, then and now

Compounded versions of semaglutide and tirzepatide were never FDA-approved. They were tolerated under the specific statutory carve-out for shortage conditions. That distinction matters, because approval — with its accompanying label, boxed warnings, pharmacovigilance, and manufacturing inspections — is what a patient is drawing on when they take an approved drug. A compounded version, even one made in a well-run 503A pharmacy, is not carrying that infrastructure.

What changed in 2025

As Novo Nordisk and Eli Lilly resolved their supply constraints, the FDA formally wound down the shortage designations for semaglutide and tirzepatide over the course of 2025 and clarified that the compounding latitude that had accompanied the shortages was ending. The agency issued warning letters to more than fifty compounders during the year and put the industry on notice that continued mass-scale compounding of these drugs would be treated as an enforcement matter.^[1]

The transition was not instantaneous or clean. Some compounders pivoted to modified formulations — combining semaglutide with vitamins, altering the peptide slightly, or moving to alternative delivery routes — arguing that these differed enough from the approved products to qualify as separate compounded medications. The FDA has been publicly skeptical of that framing.

Why this matters for readers

'Compounded semaglutide' purchased through a telehealth service in 2024 sat inside a temporary regulatory window that federal law had explicitly opened. The same purchase, from the same platform, in 2026 sits outside that window. The molecule did not change; the legal context did. A reader trying to understand press coverage of the compounded-GLP-1 industry needs both frames — the 2023–2024 shortage era and the 2025–2026 wind-down — to make sense of what is being reported.

Compounded, generic, brand — three different things

One further clarification worth making: 'compounded' is not the same as 'generic.' A generic drug is an FDA-approved version of a previously branded drug whose patents have expired; it has been reviewed for bioequivalence and manufactured under the same standards as the brand. A compounded drug is prepared per prescription (503A) or in a registered outsourcing facility (503B) and does not go through the generic approval pathway. Semaglutide has no approved generic in the United States as of early 2026; a product marketed as 'generic semaglutide' is not describing an FDA regulatory status that exists.