Semaglutide: what it is, how it is sold and how to track it

What it is

Semaglutide is a GLP-1 receptor agonist: a modified version of the natural gut hormone GLP-1 (glucagon-like peptide-1), changed so it lasts much longer in the body.

It is the active ingredient in several FDA-approved prescription medicines for type 2 diabetes and chronic weight management.

How it is usually sold

• Approved medicines: prescription pens or tablets from a pharmacy
• Compounded versions from pharmacies, which are a separate category with their own rules
• Research vials: freeze-dried powder labeled by milligrams per vial; these are not the approved medicine

Regulatory status

Semaglutide is approved only as part of specific prescription products. Vials sold "for research use only" are not approved for human use, and the FDA has warned about unapproved and counterfeit semaglutide products.

Storage basics

Sealed research vials are usually kept cold and away from light. Mixed vials are typically refrigerated and used within a window you set from the vendor's guidance. Prescription products come with their own storage directions.

How The Pep Planner helps you track it

Record the mg per vial and lot when you add stock, and use the reconstitution calculator when you mix so the amount per mL is saved with that vial. If your protocol moves through phases, add each step so the protocol card shows where you are and every change is kept in its history.

Common questions

Is semaglutide a peptide?

Yes. It is a modified peptide of 31 amino acids with a fatty acid chain attached, which helps it last longer.

Is semaglutide the same as tirzepatide?

No. Semaglutide acts on the GLP-1 receptor. Tirzepatide acts on both the GLP-1 and GIP receptors.