FDA clarifies compounding rules as GLP-1 supply stabilizes

The U.S. Food and Drug Administration issued an update on April 1, 2026 restating the rules that compounding pharmacies and outsourcing facilities must follow, saying national GLP-1 supply is beginning to stabilize. ^[1] The agency confirmed that tirzepatide and semaglutide "do not currently appear on the 503B bulks list or on FDA's drug shortage list," and spelled out when a compounded product counts as "essentially a copy" of an approved drug. ^[1]

What the update says

Compounded drugs are exempt from some normal FDA requirements only if certain conditions are met. Under section 503A of the Federal Food, Drug, and Cosmetic Act, a state-licensed pharmacy or physician must compound for an individual patient based on a prescription, and must not compound "regularly or in inordinate amounts" any drug that is essentially a copy of a commercially available product. ^[1]

FDA said it considers a compounded product essentially a copy when it has the same active ingredient or ingredients as a commercially available drug in the same, similar, or easily substitutable strength, and the commercial product can be used by the same route of administration that was prescribed. ^[1] There is one exception: a prescriber can determine and document that the compounded version contains a change producing a significant difference for a specific individual patient. ^[1]

The agency directly addressed a common practice in the GLP-1 market. It said a compounded product that combines semaglutide with another active ingredient, such as vitamin B12 (cyanocobalamin), may be considered essentially a copy when the products are given the same way — for example, by injection — and when the amounts of semaglutide and vitamin B12 in the compounded product are within 10% of the strengths of the respective commercially available drug products. ^[1] In other words, mixing in B12 does not automatically create a legally distinct product. ^[1]

FDA also described a limited enforcement threshold. It said that "at this time" it does not intend to take action against a compounder for compounding an essentially-a-copy product regularly or in inordinate amounts if that compounder fills four or fewer prescriptions of that product during a calendar month. ^[1]

For outsourcing facilities under section 503B, the rules are different. Those facilities may not compound using bulk drug substances unless the substance is on the 503B bulks list, which identifies substances for which there is a clinical need, or unless the drug made from that bulk substance is on FDA's drug shortage list at the time it is compounded, distributed, and dispensed. ^[1] Neither semaglutide nor tirzepatide meets either condition right now. ^[1]

Background

The update continues a timeline that began when the shortages ended. FDA declared the tirzepatide injection shortage resolved on December 19, 2024, and the semaglutide injection shortage resolved on February 21, 2025, after confirming with manufacturers that availability and manufacturing capacity could meet present and projected national demand. ^[1] Grace periods for compounders followed, and after federal court rulings in Outsourcing Facilities Association v. FDA in the Northern District of Texas, enforcement discretion ended for 503A compounders and, for 503B outsourcing facilities, ran until March 19, 2025 for tirzepatide and May 22, 2025 for semaglutide. ^[1]

Why it matters for patients

Many people obtained compounded semaglutide or tirzepatide during the shortage years, sometimes through telehealth sellers, and some of those products were marketed as semaglutide-plus-B12 blends. ^[1] The April 2026 update makes clear FDA's position that such blends can still be treated as copies of approved drugs. ^[1]

The four-prescriptions-per-month statement is narrow. It describes what FDA does not intend to act on, not a patient entitlement, and the agency says it may still take action for other violations, such as findings that a product may be of substandard quality or otherwise unsafe. ^[1] Practically, that means large-scale compounded supply of these two molecules does not have a clear path under the rules FDA described. ^[1]

The sources do not say what this will do to prices, how many pharmacies are affected, or whether any enforcement actions are planned. Those questions are not yet answered.

What happens next

FDA said it continues to monitor drug availability. ^[1] The bulks list and the shortage list can change, and the agency's enforcement position is described as applying "at this time." ^[1] No future dates or deadlines were announced in the April 1, 2026 update. ^[1]