Enforcement discretion is the FDA's stated intention not to take action against something it could otherwise regulate, usually for a defined period and reason. It is not a change in the law — the underlying rule still exists — but a decision about priorities. In the GLP-1 world it explains the compounding boom: while semaglutide and tirzepatide were on the FDA's shortage list, compounders were allowed to make copies, and after the shortages were declared resolved the agency announced short grace periods before it would resume enforcement.
Those windows have closed. The tirzepatide shortage was declared resolved in December 2024 and the semaglutide shortage on February 21, 2025; enforcement discretion for compounded semaglutide ended April 22, 2025 for 503A pharmacies and May 22, 2025 for 503B facilities. Since then, compounding "essentially a copy" of the approved products is not permitted outside narrow individualized cases. See pharmacy sources for GLP-1 medications.