In brief
In the United States, the Food and Drug Administration (FDA) handles the review of medicines.
With compounding, a medicine is prepared to fulfil an order rather than taken from the manufacturer’s finished stock. A registered medicine-making facility, pharmacist or doctor can prepare an order this way.
As of September 26, 2026, these preparations were not FDA-approved, including those made by well-run pharmacies.
Where compounding fits
FDA describes compounding as an option if an approved medicine cannot be obtained or does not meet the patient’s medical needs.
Among FDA’s examples are removing a dye that triggers a patient’s allergy, or changing the form for someone unable to swallow tablets.
Ask what need the proposed change is meant to meet for you. Write down the answer without replacing it with a sales term such as “custom”.
Different facilities, different oversight
As of September 26, 2026, federal law’s section 503A allowed preparation by a licensed pharmacist or doctor with a valid prescription naming the patient, subject to all other legal conditions.
Section 503B covered makers registered with FDA to prepare sterile medicines in batches, often for hospitals and clinics. The legal term was “outsourcing facilities”, and they could make batches without individual patient prescriptions.
Sterile means free of living germs.
Makers registered under 503B had to meet federal factory quality rules and were subject to FDA inspections. Medicines made under 503A were exempt from those factory rules only when they met that section’s legal conditions.
State pharmacy boards still oversaw ordinary pharmacies making medicines to order, and pharmacy quality standards still applied.
Keep approval separate
As of September 26, 2026, a batch maker’s registration with FDA under 503B did not mean FDA had approved the maker or its medicines.
FDA does not review compounded products for quality, safety or effectiveness before they reach the market.
Ask why this ingredient can be used
As of September 26, 2026, compounding rules limited which raw ingredients could be used and restricted routine copies of medicines already on sale.
For a raw drug ingredient under 503A, the law required it to meet an official drug-quality standard if one existed. If no such standard existed, the ingredient had to appear on FDA’s additional allowed-ingredient list or be a component of a drug with FDA approval.
The ingredient also needed a valid report of its test results and a maker registered with FDA.
For a change to avoid the 503A restriction on routine copies, the person writing the prescription had to decide that it made a significant difference for that named patient. A lower price alone did not count.
Ask your prescriber to identify the applicable ingredient rule and explain the change your care requires, including why that change matters. A prescription alone does not show that all these conditions have been met.