When you pick up a prescription at CVS or Walgreens, you're getting a manufactured medication—produced in a factory, packaged in standard doses, and shipped to pharmacies across the country. But that's not the only way to get medications.
Compounding pharmacies prepare customized medications for individual patients, and they've been doing it for a lot longer than drug manufacturers have existed.
📜 A Brief History
Before the rise of pharmaceutical manufacturing in the 20th century, all pharmacy was compounding. Your local pharmacist mixed every medication from raw ingredients. Mass manufacturing made standardized pills convenient, but compounding never went away—it evolved to fill gaps that manufactured drugs can't.
What Is Compounding?
Compounding is the practice of creating customized medications tailored to specific patient needs. A compounding pharmacist combines, mixes, or alters drug ingredients to create a medication that isn't commercially available in the exact form a patient needs.
Common Reasons for Compounding
- Allergies: A patient needs medication without a specific filler or dye used in the commercial version
- Dosage adjustments: A child needs a smaller dose than what's commercially available
- Different form: A patient who can't swallow pills needs liquid or topical form
- Discontinued medications: A drug is no longer manufactured but patients still need it
- Drug shortages: When manufactured supplies run out, compounders can fill the gap
- Combination products: Multiple medications combined into one for convenience
Compounding fills genuine medical needs that one-size-fits-all manufacturing can't address.
Compounding vs. Manufacturing
| Aspect | Compounding Pharmacy | Drug Manufacturer |
|---|---|---|
| FDA approval | Not required | Required (NDA/ANDA) |
| Regulation | State boards of pharmacy | FDA directly |
| Scale | Patient-specific or small batches | Mass production |
| Customization | Highly customizable | Standardized doses only |
| Cost | Often lower (no R&D costs) | Includes R&D, marketing, FDA costs |
| Prescription required | Yes (usually) | Yes (for Rx drugs) |
Types of Compounding Pharmacies
Not all compounding pharmacies are the same. Federal law distinguishes between two main categories, often called "503A" and "503B" after the relevant sections of the Food, Drug, and Cosmetic Act.
503A Pharmacies (Traditional Compounding)
These are traditional compounding pharmacies—often local, independent pharmacies with a compounding lab. They prepare medications based on individual prescriptions for specific patients.
- Regulated primarily by state boards of pharmacy
- Prepare patient-specific prescriptions
- Limited ability to prepare "stock" products without prescriptions
- Smaller batches, more personalized
There are over 7,500 compounding pharmacies in the US, and most are 503A facilities.
503B Pharmacies (Outsourcing Facilities)
These are larger facilities that voluntarily register with the FDA and follow stricter manufacturing-style regulations. They can produce medications without patient-specific prescriptions.
- FDA-registered and inspected
- Follow cGMP (current Good Manufacturing Practice) standards
- Can produce larger batches for healthcare facilities
- Subject to more rigorous quality testing
503B facilities offer higher quality assurance but there are fewer of them—several dozen nationally versus thousands of 503A pharmacies.
💡 Why This Matters for GLP-1s
When choosing a telehealth provider for compounded semaglutide, knowing whether they use a 503A or 503B pharmacy helps you understand the level of quality oversight. Both are legal, but 503B facilities have more FDA involvement and mandatory testing.
How Compounding Actually Works
Here's a simplified look at what happens when a compounding pharmacy prepares your semaglutide:
- Receive prescription: A licensed provider writes a prescription specifying the medication, dose, and form
- Source ingredients: The pharmacy obtains the Active Pharmaceutical Ingredient (API) from approved suppliers
- Prepare the formulation: A pharmacist combines the API with sterile water, buffers, and preservatives
- Quality checks: Depending on the pharmacy, this might include potency testing, sterility testing, or visual inspection
- Label and package: The medication is placed in vials with proper labeling
- Ship to patient: Cold-chain shipping maintains proper temperature
For sterile injectables like semaglutide, this happens in a cleanroom environment with specialized equipment to prevent contamination.
Is Compounding Legal?
Absolutely. Compounding is a recognized and essential part of healthcare, explicitly protected under federal law. The 2013 Drug Quality and Security Act established the modern framework for compounding regulation.
However, compounding has specific rules. Pharmacies generally cannot compound products that are "essentially copies" of commercially available drugs—unless there's a shortage or the compounded version is "significantly different" (different dosage form, different ingredients, etc.).
This is why you see compounded semaglutide combined with B12 or L-carnitine—these additions create a "significantly different" product that can be legally compounded even when brand-name semaglutide is available.
Quality Considerations
Because compounded medications aren't FDA-approved, quality varies based on the pharmacy. Here's what to look for:
Good Signs
- PCAB accreditation: Voluntary third-party certification demonstrating quality practices
- 503B registration: FDA oversight and cGMP compliance
- USP compliance: Following United States Pharmacopeia standards for compounding
- Batch testing: Testing each batch for potency and sterility
- Clear labeling: Complete information on vial labels
Questions to Ask
- Is the pharmacy 503A or 503B?
- Does the pharmacy hold PCAB accreditation?
- Does the pharmacy test each batch for potency?
- Where does the pharmacy source its API?
Reputable providers should be able to answer these questions clearly.
Compare Pharmacy Types
See which providers use 503A vs 503B pharmacies and other quality indicators.
Compare Providers →The Role of Compounding in Healthcare
Compounding serves important functions beyond just providing cheaper alternatives to brand-name drugs:
- Pediatric care: Children often need liquid forms or doses smaller than manufactured products offer
- Veterinary medicine: Animals need different doses and flavors than human medications provide
- Dermatology: Custom creams and ointments with specific ingredient combinations
- Hormone therapy: Bioidentical hormones customized to individual needs
- Pain management: Topical pain compounds to avoid oral medication side effects
- Shortage solutions: Keeping critical medications available when manufacturers can't meet demand
GLP-1 compounding became prominent during drug shortages, but compounding itself has been serving patients for decades.
Key Takeaways
- Compounding is traditional pharmacy: It predates drug manufacturing and remains an essential healthcare service
- It's legal and regulated: State boards of pharmacy oversee compounding, with additional FDA involvement for 503B facilities
- Quality varies: Not all compounding pharmacies are equal—certifications and testing matter
- 503A vs 503B: 503B facilities have more FDA oversight and stricter standards
- It fills real needs: Compounding provides solutions when manufactured drugs don't fit patient requirements