Brand versus compounded, on one page

What "brand" means here

Wegovy, Ozempic, Zepbound and Mounjaro are FDA-approved drugs. Each went through clinical trials, each has a label FDA reviewed and approved, and each is made by the company that holds the approval (Novo Nordisk for semaglutide, Eli Lilly for tirzepatide) under manufacturing rules FDA inspects. When you pick up a Wegovy pen, the dose in it, the way it was made and the instructions that come with it were all part of that approval.

What "compounded" means

Compounding is when a licensed pharmacist or physician combines, mixes or alters ingredients to make a medicine for an individual patient. It is legal under section 503A of the Federal Food, Drug and Cosmetic Act when a set of conditions is met, including a valid prescription for a specific patient. Larger "outsourcing facilities" operate under section 503B with FDA registration and inspection. Either way, FDA's own summary is the sentence to keep: compounded drugs are not FDA approved, and FDA does not verify their safety, effectiveness or quality before they are marketed (FDA, Human Drug Compounding).

For semaglutide and tirzepatide specifically, compounding grew because both brand products were on FDA's drug shortage list, and shortage status allows compounders to make what is essentially a copy of an approved drug. FDA declared the tirzepatide shortage resolved on December 19, 2024 and the semaglutide shortage resolved on February 21, 2025, with wind-down periods that have since ended. Compounded versions continue to exist under the ordinary rules, which do not allow copies of commercially available approved drugs except where a prescriber documents a clinical difference for that patient. Whether a given offer meets those rules is a question for the pharmacy's state board; the network's Compounding Explained site covers how to check.

Why "not interchangeable" is the right phrase

Three concrete differences, all from FDA's concerns page:

1. The molecule may differ. FDA has found compounded products made with salt forms (semaglutide sodium, semaglutide acetate) rather than the base semaglutide in the approved drugs, and says it is not aware of a basis for compounding with those salts.
2. The dose is not fixed by a device. Brand weight-management products come in single-dose pens; compounded products usually come in a multi-dose vial you draw from with a syringe. FDA has received reports of people taking many times the intended dose because of unit confusion or because the concentration was misunderstood.
3. There is no label. No approved dosing schedule, no approved indication, no FDA-reviewed instructions. The pharmacy's instructions and your prescriber's plan are what you have.

None of this is a claim that a particular compounded product is unsafe. It is a statement about what has and has not been checked, and about who is doing the checking.

What changes for you if you are prescribed a compounded product

• You will measure your own dose. Read your first injection and use the dose unit converter with the concentration printed on your vial. Confirm the units with the pharmacy before the first draw.
• The schedule is your prescriber's, not a label's. The week-by-week planner shows brand label schedules for orientation only. FDA's concerns page reports adverse events where compounded dosing ran faster than the label ladder.
• Storage and beyond-use dates are on the vial. They are set by the pharmacy, not by a manufacturer's stability program.
• Ask for the pharmacy's name, state license and, if offered, a certificate of analysis. The pharmacy vetting checklist turns those into a printable list.
• Cost is the usual reason. Cost basics explains why the two numbers you are comparing are not for the same product.

How this site handles it

Every page on GLP-1 Starter is written from the brand labels and the published trials because those are the documents that exist. Where a page links to a FormBlends product, it says on the same page that the product is compounded, not FDA approved, and not interchangeable with brand products. If you want a program-level look at how any GLP-1 provider, FormBlends included, discloses pharmacy sourcing and pricing, the network's FormBlends Reviews site scores them all on one published rubric.