What Is a Compounding Pharmacy? Compounded Drugs Explained
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[Glossary · Quality, storage and rules]

Compounding pharmacy

Also called compounded drug, compounded medication, compounder · Reviewed

Definition: A compounding pharmacy makes a medicine from raw ingredients for a specific patient, rather than dispensing a factory-made, FDA-approved product. FDA says compounded drugs are not FDA approved, meaning FDA does not check their safety, effectiveness or quality before they are sold. Compounded semaglutide is a well-known example.

How it works

Most compounding pharmacies work under section 503A of federal drug law: a licensed pharmacist in a state-licensed pharmacy (or a licensed physician) compounds a drug for an identified patient based on a valid prescription. Some instead register with FDA as outsourcing facilities under section 503B, which have stricter rules. The differences are covered in 503A vs 503B.

Raw drug ingredients used by a 503A pharmacy must meet a USP monograph if one exists, come from an FDA-registered maker, and come with a certificate of analysis (21 USC 353a).

Why it matters when you track doses

Compounded products often come in a vial with a concentration, not a pen with set doses. That means you draw by syringe units and do the math. FDA has received reports of people hurt by dosing errors with compounded GLP-1 drugs, some from patients measuring the wrong amount and some from health care workers miscalculating.

From label to syringe

  1. A compounded vial label reads 2.5 mg/mL.
  2. The prescribed dose is 0.25 mg. 0.25 mg / 2.5 mg/mL = 0.1 mL.
  3. On a U-100 insulin syringe, 0.1 mL = 10 units.
  4. If the next vial is a different concentration, the same 10 units is a different dose. Check every new vial label.

Dose Track saves each vial with its concentration, so the app can convert units to mg using the vial you are actually drawing from.

Common mix-ups

  • Same name, different product. Label data for Wegovy or Ozempic, such as storage times, do not transfer to compounded semaglutide.
  • Salt forms. FDA says semaglutide sodium and semaglutide acetate are different active ingredients from the approved drugs and it knows of no lawful basis for compounding with them.

Read more on Dose Track: GLP-1 units guide · U-40 vs U-100 syringes

General education drawn from labels and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your product are the final word.
503A vs 503B503A and 503B are two sections of US drug law that set the rules for compounding. A 503A pharmacy… Concentration (mg/mL)Concentration is how much drug is in each unit of volume, usually written as mg/mL, mcg/mL or units/mL. It… Beyond-use date (BUD)A beyond-use date (BUD) is the date after which a compounded or opened medicine should not be used. It is… Certificate of analysis (COA)A certificate of analysis (COA) is a document listing test results for one batch (lot) of a product: what… Research use only (RUO)Research use only (RUO) is a label phrase. In US rules it comes from labeling for in vitro diagnostic…

Frequently asked questions

Are compounded drugs FDA approved?+
No. FDA says compounded drugs are not FDA approved and are not checked for safety, effectiveness or quality before they are sold.
Is compounded semaglutide the same as Wegovy?+
It is meant to contain the same molecule, but it is a different product made by a different maker. Wegovy label data do not apply to it.
Do I need a prescription for a compounded drug?+
From a 503A pharmacy, yes: federal law ties 503A compounding to a valid prescription for an identified patient.

Sources

  1. FDA: Compounding and the FDA, questions and answers
  2. FDA: Human drug compounding laws (sections 503A and 503B)
  3. 21 USC 353a: pharmacy compounding (section 503A), Cornell LII
  4. FDA: FDA's concerns with unapproved GLP-1 drugs used for weight loss

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