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503A Compounding Pharmacy: What the Statute Requires

By Benn Bluestein-Veyra, M.Sc. Organic Chemistry · Updated 7 November 2026

A 503A compounding pharmacy is a state-licensed pharmacy in which a licensed pharmacist compounds a drug for an identified individual patient on a valid prescription, under the conditions of section 503A of the Federal Food, Drug, and Cosmetic Act, codified at 21 U.S.C. 353a. When every condition is met, the compounded drug is exempt from three requirements that otherwise apply to a drug sold in the United States: current good manufacturing practice under section 501(a)(2)(B), labeling with adequate directions for use under section 502(f)(1), and premarket approval under section 505.^[1] All other provisions of the Act continue to apply, and day-to-day oversight of the pharmacy sits with the state board of pharmacy rather than with FDA.^[2][3]

FDA describes compounding as a practice in which a licensed pharmacist or physician "combines, mixes or alters ingredients of a drug to create a medication tailored to the needs of an individual patient", and states that compounded drugs are not FDA approved, "which means the agency does not review their safety, effectiveness or quality before they are marketed."^[4] This page walks through the statute clause by clause, because the conditions are cumulative and each one corresponds to a document the pharmacy should be able to produce.^[1][3]

Section 503A grants the exemption only when every condition is met

Section 503A(a) opens with the scope of the exemption: sections 351(a)(2)(B), 352(f)(1), and 355 of title 21 "shall not apply to a drug product if the drug product is compounded for an identified individual patient based on the receipt of a valid prescription order or a notation, approved by the prescribing practitioner, on the prescription order that a compounded product is necessary for the identified patient, if the drug product meets the requirements of this section".^[1] The compounding must be performed by "a licensed pharmacist in a State licensed pharmacy or a Federal facility" or by "a licensed physician", on a prescription "made by a licensed physician or other licensed practitioner authorized by State law to prescribe drugs."^[1]

FDA reads the identified-patient language strictly. Its prescription guidance states that the compounder "must obtain a valid patient-specific prescription order" for each drug compounded under section 503A, and that where a state board authorizes prescriptions without individual patient names, "Such prescriptions, however, do not meet the requirement of a patient-specific prescription in section 503A."^[5] Section 503A(b)(1) then sets the ingredient conditions. A bulk drug substance used in the compounded product must satisfy one of three tests, in order:^[1]

• it must "comply with the standards of an applicable United States Pharmacopoeia or National Formulary monograph, if a monograph exists, and the United States Pharmacopoeia chapter on pharmacy compounding"; or
• "if such a monograph does not exist", it must be a drug substance that is a component of a drug approved by the Secretary; or
• if neither applies, it must "appear on a list developed by the Secretary through regulations issued by the Secretary under subsection (c)", which is the 503A bulks list codified at 21 CFR 216.23.

Whichever test the substance passes, two further conditions attach to it. It must be "manufactured by an establishment that is registered under section 360 of this title (including a foreign establishment that is registered under section 360(i) of this title)", and it must be "accompanied by valid certificates of analysis for each bulk drug substance".^[1] Other ingredients must meet the applicable USP or NF monograph and the USP compounding chapter. The pharmacist may not compound a product on the withdrawn-or-removed list, and may not compound "regularly or in inordinate amounts (as defined by the Secretary) any drug products that are essentially copies of a commercially available drug product."^[1]

Section 503A(b)(3) adds two product-level conditions: the drug must not be one FDA has identified by regulation as presenting "demonstrable difficulties for compounding", and it must be compounded in a state that has signed the memorandum of understanding on interstate distribution, or else the compounder must keep out-of-state distribution to no more than 5 percent of total prescription orders.^[1] The statute closes by defining the term: compounding "does not include mixing, reconstituting, or other such acts that are performed in accordance with directions contained in approved labeling provided by the product’s manufacturer".^[1]

The Drug Quality and Security Act restored section 503A after a court ruling and an outbreak

Section 503A was added by the Food and Drug Administration Modernization Act of 1997, Public Law 105-115.^[1] Its original text barred a compounder from advertising "the compounding of any particular drug, class of drug, or type of drug", and FDA’s guidance describes the present framework as applying "now that section 503A has been amended by Congress to remove the advertising and solicitation provisions that were held unconstitutional by the U.S. Supreme Court in 2002".^[1][3] The amendment came in the Drug Quality and Security Act, Public Law 113-54, enacted on November 27, 2013, which struck the advertising subsection, removed the word "unsolicited" from the prescription requirement, and created section 503B for outsourcing facilities.^[1][6]

FDA summarizes the event behind the Act plainly: "In 2012, contaminated drugs compounded by a Massachusetts pharmacy led to more than 750 cases of infection and more than 60 deaths of patients" across twenty states.^[6] The Tennessee investigation described 66 case patients with a median age of 69 and a median of 18 days from the last epidural injection to symptom onset.^[7] A six-state clinical review of 328 patients found central nervous system infection in 265 of them.^[8] A later systematic review put the final count at 751 patients and 64 deaths as of October 23, 2013.^[9]

The outbreak was the largest in a longer series. Staes and colleagues identified 11 earlier outbreaks between January 2000 and November 2012, involving 207 infected patients and 17 deaths, half of them spanning more than one state.^[10] Gudeman and colleagues catalogued potency and sterility failures in compounded products and the gaps in oversight that allowed them.^[11] A 2021 systematic review covering 1990 to 2020 identified 63 compounding errors, grouped as contamination, suprapotency and subpotency.^[12]

State boards license the pharmacy, and FDA points to the USP compounding chapters

FDA describes the division of oversight directly: "Generally, state boards of pharmacy have primary responsibility for the day-to-day oversight of state-licensed pharmacies that are not registered with FDA as outsourcing facilities. FDA does conduct surveillance and for-cause inspections of state-licensed pharmacies that are not registered as outsourcing facilities."^[2] The 503A guidance adds: "FDA expects state boards of pharmacy to continue their oversight and regulation of the practice of pharmacy, including pharmacy compounding."^[3]

The quality standard inside a 503A pharmacy comes from the statute’s reference to "the United States Pharmacopoeia chapter on pharmacy compounding".^[1] FDA’s guidance explains where that reference now lands: after the 1997 Act, "the USP moved its chapter on pharmacy compounding to chapter <795> and added chapter <797>, which specifically addresses sterile compounding and is referenced in chapter <795>."^[3] The agency contrasts this with the outsourcing facility standard: "Drugs compounded in outsourcing facilities are subject to current good manufacturing practice (CGMP) requirements. By contrast, drugs compounded by a licensed pharmacist in a state-licensed pharmacy or federal facility, or by a physician, in accordance with the conditions of section 503A of the FD&C Act, are not."^[2]

The exemption removes the manufacturing regulations in 21 CFR parts 210 and 211 and leaves in place the adulteration provision for insanitary conditions, on which most of FDA’s 503A inspection record rests.^[2][13]

Anticipatory compounding is permitted in limited quantities tied to prescription history

Section 503A(a)(2) allows a pharmacist or physician to compound "in limited quantities before the receipt of a valid prescription order for such individual patient", provided the compounding "is based on a history of the licensed pharmacist or licensed physician receiving valid prescription orders for the compounding of the drug product, which orders have been generated solely within an established relationship" with the patient or the prescriber.^[1] The statute leaves limited quantities undefined, and FDA has filled the gap with an interim compliance policy.^[5]

Under that policy, FDA does not intend to consider whether a compounder has exceeded the limited-quantity condition if the compounder "holds for distribution no more than a 30-day supply of a particular compounded drug product" to fill prescriptions not yet received, and the size of that supply "is based on the number of valid prescriptions that the compounder has received for identified individual patients in a 30-day period over the past year that the compounder selected."^[5] The guidance adds that the policy concerns inventory and "does not alter the product’s BUD", so a short beyond-use date still caps how much can sensibly be made ahead.^[5]

The anticipatory pathway is the only form of advance preparation section 503A allows. FDA’s guidance describes office stock, meaning compounded products a clinic holds to administer to patients who present with a need, and places it under section 503B: outsourcing facilities "can compound and distribute sterile and non-sterile non-patient-specific drug products to hospitals, clinics, and health care practitioners for office use."^[5] A practice that wants stock on the shelf is asking a 503B question, which the sibling page in this cluster answers.^[5]

The 5 percent interstate limit is in the statute, and its enforcement is deferred

Section 503A(b)(3)(B) ties the exemption to the state where compounding occurs. Either the state has entered into a memorandum of understanding with FDA that "addresses the distribution of inordinate amounts of compounded drug products interstate and provides for appropriate investigation by a State agency of complaints", or the compounder distributes out of state "in quantities that do not exceed 5 percent of the total prescription orders dispensed or distributed by such pharmacy or physician."^[1] FDA made a standard MOU available for signature in October 2020; several compounding pharmacies sued, and in September 2021 the district court remanded the MOU to the agency for small-business analysis.^[14]

FDA’s page now states: "FDA considers the standard MOU published in October 2020 to be suspended", and that the agency "intends to engage in notice-and-comment rulemaking regarding the statutory provisions on certain distributions of compounded human drug products, including the MOU".^[14] In October 2022 FDA extended the period before it intends to enforce the 5 percent limit "until the effective date of a final rule regarding certain distributions of compounded human drug products and publication of an updated standard MOU", and as of 7 November 2026 that entry is the most recent update on the page.^[14][15] In practice, a pharmacy’s authority to ship into another state comes from that state’s nonresident pharmacy license.^[2]

FDA inspects 503A pharmacies for cause and refers findings to state boards

FDA’s oversight of a 503A pharmacy consists of surveillance and for-cause inspection, with licensure left to the state. Its published inspection record lists, facility by facility, the Form 483 observations, warning letters, untitled letters, FMD-145 letters and referral letters to the state board of pharmacy that followed, and the 503A entries show a state referral following a 483 or a warning letter repeatedly.^[13]

The regulations implementing section 503A sit in 21 CFR part 216. Section 216.23 lists the bulk drug substances on the 503A bulks list; as of 7 November 2026 it names six, several restricted to topical use, and records four substances FDA evaluated and declined to add.^[16] Section 216.23(d) states: "Any person who represents that a compounded drug made with a bulk drug substance that appears on this list is FDA approved, or otherwise endorsed by FDA generally or for a particular indication, will cause the drug to be misbranded".^[16] Section 216.24 is the list of drug products withdrawn or removed from the market for reasons of safety or effectiveness, which "may not be compounded under the exemptions provided by section 503A(a) or section 503B(a)".^[16]

The documentation a practice should expect from a 503A pharmacy

Because each statutory condition corresponds to a record, a practice can verify a 503A supply chain with a short list. Each item is something the pharmacy already holds in order to meet the statute.^[1][3]

• A prescription order, or a prescriber-approved chart notation, naming the identified individual patient, held before the preparation leaves the pharmacy.
• The pharmacy’s home-state license and its nonresident pharmacy license for the state where the patient is located.
• A label meeting the state board’s requirements and carrying a beyond-use date assigned under the USP compounding chapters FDA references.
• A certificate of analysis for the lot of each bulk drug substance, available on request, from a supplier registered with FDA under section 510.
• Where the compounded product resembles a commercially available drug, the prescriber’s documented determination of a significant difference for that patient.

ExaVeyra’s compounded preparations reach a practice through a licensed 503A pharmacy partner on patient-specific prescriptions. The pharmacy holds the state licenses, holds its own DEA registration where a prescription involves a controlled substance, and supplies a certificate of analysis for each lot on request. Whether a compounded preparation suits a given patient, and what the prescription says, are decisions for the prescribing practitioner.^[1][5]

This article summarizes publicly available federal regulation for licensed practitioner education. It is not legal advice, medical advice, or regulatory guidance, and it does not establish that any particular product or practice is compliant. Confirm current federal and state obligations with qualified counsel.