A 503A pharmacy compounds a medication for one named patient after receiving a valid prescription for that patient. A 503B outsourcing facility registers with the FDA, is subject to current good manufacturing practice requirements and risk-based FDA inspection, and can compound sterile drugs without a prescription for an individually identified patient. If you are launching a program built on compounded medications—GLP-1s, hormones, peptides—that distinction decides which workflow you build and which diligence you owe.
The names come from sections of the federal Food, Drug, and Cosmetic Act, added by the Drug Quality and Security Act. You don't need to memorize the statute—but you do need to understand what each type of pharmacy can and can't do.
The differences at a glance
| Question | 503A pharmacy | 503B outsourcing facility |
|---|---|---|
| Patient-specific prescription required? (§ 503A, § 503B) | Yes, generally: a valid prescription for an identified individual patient | Not necessarily: also office stock, on a provider order not for an identified patient |
| Exempt from CGMP (§ 501(a)(2)(B))? | Yes, if § 503A conditions are met | No: subject to CGMP |
| Exempt from premarket approval (§ 505) and adequate directions for use (§ 502(f)(1))? | Yes, if § 503A conditions are met | Yes, if § 503B conditions are met |
| Registers with FDA as an outsourcing facility? (§ 503B) | No | Elects to register; re-registers annually |
| FDA inspection (§ 503B) | Not on a federal outsourcing-facility schedule | On a risk-based FDA schedule |
| Reporting to FDA (§ 503B(b)) | No § 503B product report | Product report at registration and each June and December, plus adverse events |
| Primary day-to-day oversight | State boards of pharmacy | State boards plus the federal § 503B framework |
| Is the compounded product FDA-approved? | No | No: registration is not approval |
Read the table as an operating-model aid, not a legal classification tool. Which section applies turns on the preparation, the facility, the prescription process, and the distribution model—and a pharmacy can be in one lane for some products and not others.
503A pharmacies
A 503A pharmacy compounds medications for an individual patient based on a specific prescription. This is the model most direct-to-patient telehealth programs rely on: a provider writes a prescription for a named patient, and the pharmacy prepares that patient's medication. 503A pharmacies are primarily overseen by state boards of pharmacy.
When 503A fits
- Direct-to-patient telehealth programs with individual prescriptions
- Personalized formulations and dosing
- Most GLP-1, hormone, and peptide programs run through licensed 503A partners
503B outsourcing facilities
A 503B outsourcing facility is a facility at one geographic location that compounds sterile drugs, has elected to register with the FDA as an outsourcing facility, and complies with the requirements of section 503B. It may distribute without a prescription for an identified individual patient, which is what makes office stock possible. In exchange, it carries a heavier federal load: CGMP compliance, annual re-registration, risk-based FDA inspection, adverse event reporting, and a drug product report twice each year.
When 503B fits
- Clinics and organizations buying office stock
- Higher-volume, batch production needs
- Settings that require FDA-registered manufacturing standards
The conditions the exemptions depend on
Neither section is a status a pharmacy holds permanently. Both are sets of conditions, and a product that fails them is simply an unapproved new drug. Two conditions cause most of the trouble for telehealth programs.
Which bulk drug substances may be used
Under section 503A, a bulk drug substance must comply with an applicable United States Pharmacopeia or National Formulary monograph if one exists; be a component of an FDA-approved drug product if no monograph exists; or appear on FDA's 503A bulks list if neither is true. It must also be accompanied by a valid certificate of analysis and have been made by an establishment registered with FDA.
Under section 503B the test is different: the substance must appear on the 503B bulks list, which FDA populates only where it finds a clinical need for outsourcing facilities to compound from bulk rather than from an approved drug, or the compounded drug product must appear on FDA's drug shortage list at the time of compounding, distribution, and dispensing.
Whether the preparation is essentially a copy
Both sections restrict compounding a drug that is essentially a copy of a commercially available or approved product. Under 503A, a change made for an identified individual patient that produces a significant difference for that patient, as determined by the prescribing practitioner, can take a preparation outside the restriction. Under section 503B(d)(2)(A) that prescriber determination is not available in the same way, so an outsourcing facility cannot rely on it to make a nearly identical product. If your program's value proposition is a dose or a combination that an approved product already offers, this is the paragraph to bring to counsel.
What changed for compounded GLP-1s
Because several of those conditions depend on whether a drug is on FDA's drug shortage list, the GLP-1 shortages made a large amount of compounding lawful and their resolution made it unlawful again. FDA determined the tirzepatide injection shortage resolved on October 2, 2024, and later determined the semaglutide injection shortage resolved as well. FDA then set dated periods during which it did not intend to act on violations arising from shortage-dependent conditions: for outsourcing facilities compounding tirzepatide, until March 19, 2025; for outsourcing facilities compounding semaglutide, until May 22, 2025. For state-licensed pharmacies and physicians compounding semaglutide under 503A, that period ended following the district court's April 24, 2025 denial of a preliminary injunction.
The story has not stopped. On April 30, 2026 FDA proposed to exclude semaglutide, tirzepatide, and liraglutide from the 503B bulks list, finding no clinical need for outsourcing facilities to compound them from bulk substances, and took comments through June 29, 2026. That is a proposal rather than a final determination, and this page does not predict where it lands. The point for a founder is structural: a program whose economics depend on one compounded molecule is exposed to a list it does not control.
What it means for your brand
Match the pharmacy type to how your program actually dispenses. Most direct-to-patient telehealth brands run on 503A partners, but the right answer depends on your model. Whatever you choose, three things matter:
- Confirm licensing in every state you ship to
- Prioritize partners with strong quality controls and clear documentation
- Make sure dispensing and shipping follow the rules for each patient's state
The diligence that sits behind those three lines—verifying the exact facility rather than the parent brand, reading FDA's published inspection findings, and contracting for recalls and continuity—is laid out step by step in how to choose and verify a telehealth compounding pharmacy.
Compliance considerations
Compounded medications occupy a nuanced regulatory space, and the rules evolve. Working with licensed, reputable partners—and keeping clear documentation of dispensing—protects both your patients and your brand. Two claims to keep out of your marketing entirely: that a compounded product is FDA-approved, and that a partner's FDA registration or inspection is a guarantee of compliance. Neither is true, and both are the kind of statement a regulator reads back to you.
Key takeaways
- 503A compounds per patient from a specific prescription; 503B compounds in batches under FDA-registered standards and CGMP.
- Most direct-to-patient telehealth runs on licensed 503A pharmacies.
- The exemptions are conditions, not a status: bulk drug substance rules and the essentially-a-copy restriction decide whether a given preparation qualifies.
- Shortage-list status changes what may be compounded, as the GLP-1 timeline showed twice.
- Always confirm state licensing and quality controls, whichever type you use.
MDLaunchr connects your brand to vetted, licensed compounding partners with direct-to-patient fulfillment—so the medication side of your program is handled correctly without you negotiating a single contract.
Written and reviewed by MDLaunchr's clinical and compliance team. We build white-label telehealth infrastructure for founders, creators, and healthcare operators—covering providers, pharmacy, technology, and compliance.
This article is for general informational and educational purposes only and is not medical, legal, or regulatory advice. It does not create a provider-patient relationship and should not be used to diagnose or treat any condition. Telehealth and compounding regulations vary by state and change over time—consult qualified legal, clinical, and compliance professionals before launching or operating a telehealth program.
Frequently asked questions
What is the difference between a 503A pharmacy and a 503B outsourcing facility?
A 503A pharmacy compounds for an individual patient after receiving a valid prescription for that patient, and can qualify for exemptions from premarket approval, adequate directions for use, and CGMP requirements when the conditions of section 503A are met. A 503B outsourcing facility elects to register with FDA, is subject to CGMP requirements and risk-based FDA inspection, and can distribute either on a patient-specific prescription or in response to a health care provider's order that is not for an identified patient.
Are compounded drugs FDA-approved?
No. Compounded drugs are not FDA-approved and have not gone through the premarket review that approved drugs undergo. This is true of products from 503A pharmacies and from registered 503B outsourcing facilities alike: registration is not approval of the products a facility makes.
Which type does a direct-to-patient telehealth program usually use?
Most direct-to-patient telehealth programs run on licensed 503A pharmacies, because the model is already built around a prescription written for a named patient. That is a pattern, not a rule. The right answer depends on the preparation, whether sterile compounding is involved, the distribution model, and the states where patients are located.
Can a 503B facility compound anything it wants from bulk drug substances?
No. An outsourcing facility may compound a drug product from a bulk drug substance only if the substance appears on the 503B bulks list, which FDA maintains for substances it has found a clinical need for, or if the compounded drug product appears on FDA's drug shortage list at the time of compounding, distribution, and dispensing.
Does either type replace state pharmacy licensing?
No. Sections 503A and 503B are federal conditions. A pharmacy or outsourcing facility still holds state licenses and permits, and shipping into a state can raise its own non-resident requirements. Confirm licensure in every state you ship to, and get state-specific review before you launch or expand.
- FD&C Act Provisions that Apply to Human Drug Compounding (FDA)
- Information for Outsourcing Facilities (FDA)
- Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act (FDA)
- 503B Bulk Drug Substances List (FDA)
- Compounding when Drugs are on FDA's Drug Shortages List (FDA)
- FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize (FDA)