What is the difference between a compounded and an FDA-approved medicine?

An FDA-approved medicine has been reviewed by the agency for safety, effectiveness and quality before it can be sold. A compounded medicine is prepared by a pharmacy, often to a per-patient recipe, and has not been through that review. In the FDA’s own words, compounded drugs are not FDA-approved, and the agency does not verify their safety, effectiveness or quality before they reach a patient.

That is a statement about the regulatory route, not a verdict on any individual pharmacy. Compounding exists for real clinical reasons, including allergies to an ingredient in a manufactured product or a form someone cannot take. The FDA has also published specific concerns about compounded versions of weight-management medicines, including adverse event reports it has received.

If you are choosing between the two, the useful move is to read the FDA pages directly and then ask your prescriber why they are recommending one route over the other for you specifically. That is a question they can answer and a comparison page cannot.