Guide
What is a 503A compounding pharmacy?
A 503A compounding pharmacy is a state-licensed pharmacy that makes medicines for individual patients with a prescription, under section 503A of the federal Food, Drug, and Cosmetic Act. Its state board of pharmacy does most of the oversight, and its compounded drugs are not FDA approved. A 503B outsourcing facility is the other kind: it registers with FDA, follows manufacturing-grade rules, is inspected by FDA and can make drugs for clinics without a prescription for each patient.
Side by side
What is the difference between 503A and 503B?
FDA's own summary: 503A drugs must be compounded on patient-specific prescriptions, while outsourcing facilities follow manufacturing standards, are inspected by FDA and may fill a clinic's order for office stock. The details:
| 503A compounding pharmacy | 503B outsourcing facility | |
|---|---|---|
| Law | FD&C Act section 503A, enacted 1997 and amended in 2013 | FD&C Act section 503B, created by the Drug Quality and Security Act on November 27, 2013 |
| Who compounds | A licensed pharmacist in a state-licensed pharmacy or federal facility, or a licensed physician | A facility that elects to register with FDA, with compounding done by or under the direct supervision of a licensed pharmacist |
| Prescription | Required for an identified patient. Limited advance compounding is allowed based on a history of prescriptions | With or without a patient-specific prescription |
| Office stock for clinics | Not allowed without a prescription for each patient | Allowed, labeled "Office Use Only" |
| Main regulator | State board of pharmacy. FDA inspects mainly for surveillance or after a complaint | FDA, on a risk-based inspection schedule |
| Registered with FDA | Generally no; licensed by the state | Yes, every year, with an annual fee ($22,074 for fiscal 2027; $7,142 for a small business) |
| Manufacturing standard | Exempt from current good manufacturing practice (CGMP) if section 503A's conditions are met. The statute points to the USP chapter on pharmacy compounding | Must meet CGMP. FDA's guidance on how is still a January 2020 draft |
| Adverse events | No federal requirement to report to FDA | Required: serious, unexpected events within 15 calendar days |
| Product reports to FDA | None | At registration, then every June and December |
| Labeling | No federal 503B-style label list | Must say "This is a compounded drug", plus lot, dates, facility contact and "Not for resale" |
| Bulk ingredients | Must have a USP or NF monograph, be part of an FDA-approved drug, or be on the 503A bulks list | Must be on the 503B bulks list (five substances) or used for a drug on FDA's shortage list. FDA's interim 503B Category 1 policy is non-enforcement, as on the 503A side |
| Copies of marketed drugs | May not compound copies of a commercially available drug "regularly or in inordinate amounts". FDA says a lower price alone does not make a compounded version significantly different | Not allowed unless the drug is in shortage or a prescriber documents a clinical difference |
| FDA approved? | No | No. If a facility meets every condition of section 503B, its drugs are exempt from the approval requirement. FDA registration and inspection do not make them approved |
| How to check one | The state board of pharmacy license lookup | FDA's list of registered outsourcing facilities, plus the state board for state actions |
An outsourcing facility does not have to be a licensed pharmacy, but it must compound sterile drugs. FDA listed 98 registered outsourcing facility locations as of September 30, 2026. FDA says states oversee the vast majority of the thousands of compounders in the US, most of which do not register with FDA.
Ingredients
What can a 503A pharmacy compound?
When a 503A pharmacy compounds from a bulk drug substance (the raw active ingredient), that ingredient must fit one of three routes in the statute, be made by an FDA-registered establishment and come with a valid certificate of analysis:
Route 1
A USP or NF monograph
The ingredient has a United States Pharmacopeia or National Formulary monograph and meets it.
Route 2
Part of an FDA-approved drug
If no monograph exists, the ingredient is a component of a drug FDA has approved.
Route 3
The 503A bulks list
If neither applies, the ingredient is on FDA's list at 21 CFR 216.23, which holds six substances and has not changed since 2019.
While FDA reviews ingredients nominated for the bulks list, it says it does not intend to take action against compounding from those in its interim Category 1, if every other condition is met. That is a policy of non-enforcement, not one of the three routes.
Other limits apply too, including these. A 503A pharmacy may not regularly compound copies of a commercially available drug, and FDA's guidance says a lower price alone does not make a compounded version significantly different. The statute bars compounding drugs FDA has listed as withdrawn or removed from the market for safety or effectiveness reasons. And FDA says biological products are not eligible for the compounding exemptions under either 503A or 503B.
Shipping across state lines
Can a 503A pharmacy ship to other states?
Section 503A says a pharmacy in a state without an FDA agreement may not send compounded drugs out of state in quantities above 5 percent of the total prescription orders it dispenses or distributes.
FDA released a standard agreement in October 2020 and a court sent it back in September 2021. In 2022 FDA said it considers that agreement suspended, and in October 2022 it said it does not intend to begin enforcing the 5 percent limit until a final rule takes effect and an updated agreement is published. As of this page's check, no such rule has been proposed or published.
So the 5 percent cap is in the law, FDA has said it does not intend to enforce it for now, and FDA says it does not expect states that signed the 2020 agreement to carry it out while it is suspended. States can still act under their own laws.
Before you partner
Six questions to ask any 503A pharmacy
A peptide program is only as sound as the pharmacy filling it. These are the questions that matter, and why.
1.Which states are you licensed in?
FDA tells consumers to look up an online pharmacy in the license database of their own state's board of pharmacy, and not to use it if it is not listed. For a program, that means a license in each state your clients live in.
2.Under which 503A route does each ingredient qualify?
A USP or NF monograph, a component of an FDA-approved drug, or the 503A bulks list. FDA's interim Category 1 is a policy of non-enforcement, not a route in the statute, and FDA does not intend to add ingredients nominated on or after January 7, 2025 to it.
3.Is every bulk ingredient from an FDA-registered manufacturer, with a certificate of analysis?
Section 503A requires both for each bulk drug substance.
4.Which USP standards do you follow for sterile work?
USP <797> covers sterile compounding and <795> nonsterile; the current versions became official on November 1, 2023. Sterile preparations include injections.
5.How do you handle and report adverse events?
Federal law does not require a 503A pharmacy to report them to FDA, so ask what the pharmacy does instead.
6.When were you last inspected, and by whom?
State boards carry most of the day-to-day oversight. FDA inspects a 503A pharmacy mainly for surveillance or after a complaint.
For peptide programs
Why do telehealth peptide programs use 503A pharmacies?
Section 503A is built around a prescription for one identified patient. A telehealth program in which a licensed clinician reviews each patient and writes each prescription fits that model. A 503B facility can also fill patient prescriptions and is registered with and inspected by FDA; its distinguishing permission is office stock for clinics. By statute its bulk ingredients must be on the 503B list, which holds five substances, or be used for a drug in shortage, and FDA also does not intend to act against 503B compounding from its 503B Category 1 while it reviews them.
On ConduitMD, prescriptions are written by clinicians of an independent medical practice and filled by state-licensed pharmacies compounding under section 503A that ship to the patient; the operator never buys or holds medication. Which ingredients a pharmacy may compound is governed by the routes above. How a program is structured is covered in the guide to starting a peptide program.
Sources
Where this page comes from
The statute and FDA first. Verbatim quotes and dates are kept with the page's research notes.
- FD&C Act section 503A (21 U.S.C. 353a)
Who may compound, the prescription requirement, the ingredient routes, copies and the 5 percent provision.
- FD&C Act section 503B (21 U.S.C. 353b)
Outsourcing facilities: registration, CGMP, reporting, labeling and the no-resale rule.
- FDA, Human Drug Compounding Laws
FDA's one-paragraph comparison of 503A and 503B.
- FDA, Compounding and the FDA: Questions and Answers
Oversight by state boards, CGMP, and "Compounded drugs are not FDA-approved."
- FDA, Registered Outsourcing Facilities
The weekly list of 503B facilities; 98 locations as of September 30, 2026.
- Federal Register, 87 FR 63947 (October 21, 2022)
FDA suspends the 2020 standard agreement and extends non-enforcement of the 5 percent limit.
- FDA guidance, essentially copies under section 503A (January 2018)
What counts as a copy of an approved drug, and why price is not a significant difference.
- FDA, 503B Bulk Drug Substances List
The five substances on the 503B list.
- 21 CFR 216.23, the 503A bulks list
Six substances, unchanged since 2019.
- FDA, Bulk Drug Substances Used in Compounding Under Section 503A
The interim Category 1 non-enforcement policy, and no new categorizations after January 7, 2025.
- FDA, Bulk Drug Substances Used in Compounding Under Section 503B
The matching interim Category 1 policy for outsourcing facilities.
- FDA draft guidance, CGMP for outsourcing facilities (January 2020)
Still a draft.
- FDA, Compounding Information for States
States oversee most of the thousands of US compounders; FDA intends rulemaking on 503A distribution.
- FDA, MOU on certain distributions of compounded drugs
The 2020 standard agreement, treated as suspended since 2022.
- FDA, Concerns with Unapproved GLP-1 Drugs Used for Weight Loss
Federal law does not require 503A pharmacies to report adverse events to FDA.
- Federal Register, outsourcing facility fees for fiscal 2027
The annual 503B establishment fee.
- FDA BeSafeRx, Locate a State-Licensed Online Pharmacy
How to check a pharmacy's license with the state board.
- USP General Chapter <797>
Sterile compounding standard; the current version became official November 1, 2023.
- USP General Chapter <795>
Nonsterile compounding standard; also official November 1, 2023.
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Frequently asked
503A pharmacy questions
What is a 503A compounding pharmacy?
A state-licensed pharmacy that compounds medicines for individual patients with a prescription, under section 503A of the Federal Food, Drug, and Cosmetic Act. If it meets that section's conditions, its compounded drugs are exempt from FDA approval, current good manufacturing practice and certain labeling requirements. State boards of pharmacy carry most of the day-to-day oversight.
What is the difference between 503A and 503B?
A 503A pharmacy is licensed by its state and compounds for individual patients with a prescription. A 503B outsourcing facility registers with FDA, must follow current good manufacturing practice, is inspected by FDA on a risk-based schedule, reports adverse events and its products to FDA, and may make drugs without a patient-specific prescription for clinics to keep as office stock.
Are drugs from a 503A pharmacy FDA approved?
No. FDA says compounded drugs are not FDA approved, meaning FDA does not review their safety, effectiveness or quality before they are sold. That is also true of drugs from a 503B outsourcing facility.
Is a 503A pharmacy regulated by the FDA?
Both FDA and the state, but mostly the state. FDA says state boards of pharmacy have primary responsibility for day-to-day oversight of state-licensed pharmacies, and FDA inspects them mainly for surveillance or after a complaint such as a serious adverse event.
Can a 503A pharmacy ship to other states?
Federally, yes for now. Section 503A caps out-of-state distribution of compounded drugs at 5 percent of a pharmacy's total prescription orders in states without an FDA agreement, but FDA treats its 2020 standard agreement as suspended and has said it does not intend to begin enforcing the 5 percent limit until a final rule takes effect and an updated agreement is published. No such rule had been published as of October 18, 2026. Separately, check that the pharmacy is licensed by the board of pharmacy in the patient's state.
Can a 503A pharmacy sell to clinics for office use?
Not under section 503A, which requires a prescription for an identified patient. Compounding for office stock is what section 503B outsourcing facilities are allowed to do.
Do 503A pharmacies have to follow USP 797?
Section 503A refers to the United States Pharmacopeia's compounding chapter, and USP <797> is the standard for sterile compounding; the current version became official on November 1, 2023. State boards of pharmacy carry the day-to-day oversight of 503A pharmacies, so ask the pharmacy which standards its board inspects it against.
How many 503B outsourcing facilities are there?
FDA's registered outsourcing facility list showed 98 facility locations as of September 30, 2026. A company can run more than one, and the list updates weekly.
Nothing on this page is legal advice. Compounding rules and FDA policy change; this page was last checked against FDA sources on 18 October 2026. ConduitMD provides software and management services to an independent medical practice and its partners; it does not prescribe, compound or dispense.