The An active pharmaceutical ingredient is the substance in a drug that is intended to furnish its pharmacological activity or other direct effect. In compounding law the same thing is called a bulk drug substance. In a compounded GLP-1 prescription from BrightSide, it is semaglutide or tirzepatide, which the pharmacy combines with other ingredients to make the finished vial.
How does an active pharmaceutical ingredient apply to compounded GLP-1 treatment?
Semaglutide or tirzepatide is the active pharmaceutical ingredient in a compounded GLP-1, and federal law controls where a pharmacy gets it. Under section 503A the ingredient has to comply with a United States Pharmacopeia or National Formulary monograph if one exists, or be a component of an FDA-approved drug, or appear on FDA's bulks list. It has to be made by an establishment registered with FDA, and it has to come with a valid certificate of analysis. FDA added a border control for this group of ingredients. Under Import Alert 66-80, FDA can detain shipments of GLP-1 active ingredients unless the product and the manufacturer are on the alert's green list. FDA says the alert does not stop legal importation from compliant manufacturers and does not create new limits on legal compounding. BrightSide's compounded semaglutide is filled by a licensed pharmacy, and our pharmacy network page covers how we choose pharmacies.
What does active pharmaceutical ingredient mean at the pharmacy?
At the pharmacy, the active pharmaceutical ingredient is the starting material a pharmacist turns into a finished medication. FDA regulations define a finished drug product as a finished dosage form, such as a tablet, capsule or solution, that contains at least one active pharmaceutical ingredient, generally with other ingredients. The same regulations say that bulk drug substance, the phrase used in sections 503A and 503B, has the same meaning as active pharmaceutical ingredient. FDA's import alert explains why the source matters in compounding. Ingredient manufacturers are subject to current good manufacturing practice. Pharmacies that compound under section 503A are exempt from it, including the requirement to ensure that an ingredient meets specifications for impurities or potency. The alert reports that 21 percent of the 48 GLP-1 ingredient sites FDA evaluated were noncompliant.
What should a patient check?
Check that the medication came from a licensed pharmacy on a prescription, and that the label is what it claims to be. FDA is aware of fraudulent compounded semaglutide and tirzepatide sold with false information on the label. In some cases the pharmacy named on the label does not exist. In others the label names a licensed pharmacy that did not compound the product. FDA has also warned companies that sold unapproved drugs containing semaglutide or tirzepatide directly to consumers under false labels such as "for research purposes" or "not for human consumption", and it urges consumers not to buy them. FDA recommends filling a prescription at a state-licensed pharmacy. Ask the company which pharmacy fills the prescription, then confirm that pharmacy's license with its state. For Washington patients, our Washington page names Nordic Pharmacy in Poulsbo, Washington as the pharmacy that fills the prescription.
| Term | Meaning |
|---|---|
| Active pharmaceutical ingredient | A substance intended for a finished drug product and intended to furnish pharmacological activity or other direct effect |
| Bulk drug substance | Has the same meaning as active pharmaceutical ingredient, as the term is used in sections 503A and 503B |
| Finished drug product | A finished dosage form, such as a tablet, capsule or solution, that contains at least one active pharmaceutical ingredient |
Common questions
Is an active pharmaceutical ingredient the same thing as a bulk drug substance?
Yes, in compounding. FDA's regulation at 21 CFR 207.1 says bulk drug substance, as referenced in sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act, has the same meaning as active pharmaceutical ingredient. FDA's consumer pages on GLP-1 drugs use the two terms interchangeably.
Where do GLP-1 active ingredients come from?
From manufacturers around the world. FDA's import alert says that during the shortages, active ingredients used to compound GLP-1 drugs were supplied by manufacturers in China, India and Europe, among other places. Federal law requires the manufacturer to be registered with FDA, and FDA can detain shipments from makers that are not on its green list.
Related terms
- Certificate of analysis (COA): the batch report that has to come with each active ingredient.
- Bulks list (503A bulk drug substances): FDA's list of ingredients a pharmacy can use when no other route applies.
- Compounded medication: what a pharmacy makes from the active ingredient.
- 503A compounding pharmacy: the pharmacy that buys the ingredient and makes the vial.
Sources
- 21 CFR 207.1, Definitions: https://www.govinfo.gov/content/pkg/CFR-2025-title21-vol4/xml/CFR-2025-title21-vol4-sec207-1.xml
- 21 U.S.C. 353a, Pharmacy compounding (section 503A of the Federal Food, Drug, and Cosmetic Act): https://www.govinfo.gov/content/pkg/USCODE-2024-title21/html/USCODE-2024-title21-chap9-subchapV-partA-sec353a.htm
- FDA, Import Alert 66-80, published October 9, 2026: https://www.accessdata.fda.gov/cms_ia/importalert_1186.html
- FDA, FDA's concerns with unapproved GLP-1 drugs used for weight loss, content current as of October 1, 2026: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
Compounded medications are not FDA approved. They are prescribed by a licensed clinician and filled by a licensed 503A pharmacy.
