Weight care | 6 min read
Compounded GLP-1s vs. FDA-Approved Semaglutide and Tirzepatide: What's the Difference?
Editorial draft — clinical review pending.
Short answer: A compounded GLP-1 is a preparation made by a pharmacy for an individual patient. It is not FDA approved, and the FDA does not review it for safety, effectiveness or quality before it is dispensed. An FDA-approved brand or generic has gone through that review. Both can be prescribed, but they are not interchangeable, and you should know which one you are receiving. [1]
Key takeaways
- "Compounded" and "generic" are different legal categories. A generic must show it matches the approved drug; a compounded preparation does not. [1]
- The FDA has documented dosing errors and counterfeit or mislabeled GLP-1 products, mostly from outside licensed pharmacies. [2]
- The right question is not only the price. It is what the product is, who made it, and what support comes with it.
Three categories, three pathways
FDA-approved brands such as Wegovy (semaglutide) and Zepbound (tirzepatide) were tested in large clinical trials, and the FDA reviewed their manufacturing.
FDA-approved generics must show they contain the same active ingredient in the same strength and dosage form and work the same way as the brand.
Compounded preparations are made by state-licensed pharmacies or registered outsourcing facilities. Compounding has a legitimate role, for example when a patient needs a formulation the approved product does not offer. But the finished product is not FDA approved, and calling it a generic is inaccurate. [1]
Why this matters for GLP-1s specifically
Demand for semaglutide and tirzepatide outpaced supply in 2022 to 2024, and compounding expanded quickly. The FDA has since declared both shortages resolved, which narrows when copies of approved drugs can legally be compounded. [2]
The FDA has also received reports of patients hospitalized after measuring the wrong dose from multidose vials, of products with incorrect labels, and of counterfeit products sold online. Many of these issues came from sellers operating outside legitimate pharmacies. [2]
None of this means every compounded prescription is unsafe. It means the source and the instructions matter more than they do with a prefilled brand-name pen.
Questions to ask any provider
- Is this an FDA-approved product or a compounded preparation?
- Which pharmacy makes and dispenses it, and is it state licensed or an FDA-registered outsourcing facility?
- Does it contain anything besides the active ingredient, such as added vitamins? If so, what evidence supports that combination?
- Is it a prefilled pen or a vial I draw up myself? Who will show me how to measure the dose?
- What does the monthly price include: clinician visits, medication, supplies, shipping and follow-up?
A trustworthy service will answer each of these in writing without hesitation.
Safe-use basics
Never convert a dose from one product to another yourself. Milligrams on a brand pen and units on a syringe are not the same measurement. Do not use a friend's dosing chart. If a package, label or concentration looks different from your last shipment, call the pharmacy before injecting.
Frequently asked questions
Is compounded semaglutide the same as Wegovy?
It contains the same named active ingredient, but it is a different product that has not been FDA approved or tested in the same trials.
Is compounding legal?
Yes, under specific federal and state rules. Those rules limit when copies of commercially available approved drugs can be made. [1]
How do I know if a pharmacy is legitimate?
Ask for its name and license, then check it with your state board of pharmacy. Be cautious of sites that sell without a prescription.
Next step
HerScripts clinicians explain exactly which product is being prescribed, where it comes from, and how to use it. See how weight care works.
Sources
[1] FDA, Compounding and the FDA: Questions and Answers
[2] FDA, Concerns with unapproved GLP-1 drugs used for weight loss
Educational information, not personal medical advice. Care decisions require an individual clinical evaluation.