Why there are two kinds of compounding pharmacy
Compounding means a pharmacist mixing or altering ingredients to make a medicine that is not available off the shelf in the needed form. For most of its history, it was a local, patient-by-patient practice. That changed after 2012, when contaminated injections from a Massachusetts compounding pharmacy caused a fungal meningitis outbreak.
The FDA’s summary of human drug compounding laws puts the toll at more than 750 infections and more than 60 deaths across 20 states. Congress responded with the Drug Quality and Security Act, signed on November 27, 2013. It confirmed the existing rules for traditional pharmacy compounding, known as section 503A, and created a new, voluntary category of larger-scale compounders under section 503B.
What “not FDA-approved” means
Whichever section applies, the product in your hand is not an FDA-approved drug. The FDA’s compounding questions and answers put it plainly: the agency does not verify the safety, effectiveness or quality of compounded drugs before they are marketed. It also notes what can go wrong with poor practices, such as contamination or a product that contains too much or too little of the active ingredient.
That does not make compounding a bad thing. The same FDA page describes its legitimate purpose: a patient who is allergic to a dye in an approved tablet, or who cannot swallow pills and needs a liquid, may need a version made just for them. The two sections below are about how the system tries to keep that kind of medicine safe.
503A: compounding for an individual patient
A 503A pharmacy is a state-licensed pharmacy, or a physician, compounding for a specific person. Its products are exempt from FDA approval, from current good manufacturing practice (CGMP) rules and from certain labeling requirements, but only if they meet several conditions. The central one is that each product is made for an identified individual patient, based on a valid patient-specific order from a licensed clinician.
Other limits apply. A 503A pharmacy may not regularly compound copies of a commercially available drug. In an April 2026 update, the FDA said it does not intend to act against a pharmacy that fills four or fewer orders of such a copy in a calendar month, a sign of how narrow that allowance is. Bulk ingredients must also meet legal criteria, which is why peptides under review cannot simply be compounded on demand.
Oversight is mostly local. According to the same FDA questions and answers, state boards of pharmacy have primary responsibility for day-to-day oversight of 503A pharmacies, while the FDA conducts surveillance and for-cause inspections.
503B: FDA-registered outsourcing facilities
An outsourcing facility is a compounder that has chosen to register with the FDA under section 503B. In exchange for broader permission to distribute, it accepts tighter rules. The FDA’s outsourcing facility page lists the core requirements:
- compliance with CGMP, the same family of quality rules that apply to drug manufacturers;
- FDA inspections on a risk-based schedule;
- reporting adverse events to the FDA;
- reporting the drugs it compounded every June and December.
Outsourcing facilities can fill patient-specific orders or supply clinics and hospitals with office stock, with no named patient. They can only use bulk ingredients that appear on the 503B bulks list or that are needed for a drug on the FDA’s shortage list.
The FDA publishes a list of registered outsourcing facilities, updated weekly, showing each facility’s last inspection date, whether an inspection form noting problems was issued and what action followed.
503A vs 503B at a glance
| 503A pharmacy | 503B outsourcing facility | |
|---|---|---|
| Who it serves | Identified individual patients | Patients and clinic or hospital office stock |
| Primary regulator | State board of pharmacy | FDA |
| Manufacturing rules | Pharmacy standards; not CGMP | CGMP |
| FDA inspections | Surveillance and for-cause | Risk-based schedule |
| Adverse event reporting to FDA | Not required | Required |
| FDA-approved products? | No | No |
What it means for peptides, Trimix and GLP-1 medicines
Peptides. Whether a peptide can be compounded depends on bulk ingredient rules, not just on demand. BPC-157 and TB-500 were recommended for the 503A list in July 2026, but no final rule exists. Our article on the FDA’s 2026 peptide decisions explains the status. Biologics cannot be compounded under either section, which is why tesamorelin and HCG are only available as approved products; our article on why compounded HCG disappeared covers that change.
Trimix. No FDA-approved product combines alprostadil, papaverine and phentolamine, so every Trimix injection is compounded. That makes the pharmacy, its storage instructions and its beyond-use dating especially important.
GLP-1 medicines. In its April 2026 update, the FDA said semaglutide and tirzepatide are on neither its shortage list nor the 503B bulks list, so outsourcing facilities cannot compound them from bulk. A 503A pharmacy may still compound for an individual patient, but not routine copies of a commercial product. Our page on compounded GLP-1 rules follows those changes.
None of this applies to products labeled “for research use only,” which sit outside both systems. Our article on research-use-only peptides explains why.
Questions to ask about any compounded medicine
Whoever recommends a compounded product, you can ask:
- Which pharmacy makes it, and is it a 503A pharmacy or a 503B outsourcing facility?
- Is the pharmacy licensed in California, or licensed to ship here?
- Why is a compounded version being used instead of an approved one?
- How should it be stored, and what is its beyond-use date?
- Who do I call if the product looks, feels or works differently from the last batch?
Checking a California license yourself
You do not have to take a pharmacy’s word for its status. California pharmacy licenses can be looked up on the DCA License Search, run by the Department of Consumer Affairs, which includes the Board of Pharmacy, so you can confirm a license is current. If the pharmacy is outside California, ask whether it is licensed to ship here, then look that up too. For an outsourcing facility, the FDA’s registered facility list shows its most recent inspection.
A word on buying compounded medicine online
The FDA’s questions and answers also caution that people who buy compounded drugs online, including through telehealth platforms, may not know which compounder produced the drug, or whether that compounder meets quality standards and is properly licensed. The practical fix is simple: whoever recommends a compounded product should be able to name the pharmacy, and you should be able to check it. If a seller cannot or will not tell you, treat that as your answer.
How Ultimate Male works with compounding pharmacies
Compounded medicines at Ultimate Male come from licensed U.S. compounding pharmacies, including our partner pharmacies Paragon Meds, Pellecome and Anazao Health. Where an FDA-approved product fits, such as tesamorelin, that is what we use. Within our peptide therapy program, we only discuss peptides that can lawfully be supplied, and we tell you plainly when one cannot.
You are welcome to ask which pharmacy made your medicine and how it is regulated. Bring that question, and any product you are already using, to the free 10-minute call.
