GLP-1 Agonist List: Types, Formats, and FDA Status Explained
"GLP-1 agonist" is the name of a family of medications, not a single drug. The family has grown over two decades, and its members differ in how they act, how often they are taken, and how they are regulated. A bare list of names tells you little. This guide sorts the family four different ways so you can see where any particular medication fits. It is educational and does not replace medical advice.
What makes a medication a GLP-1 agonist
GLP-1 is a hormone released by the gut after eating. An agonist is a substance that activates a receptor. A GLP-1 receptor agonist, then, is a medication that switches on the same receptors as the natural hormone, while lasting much longer in the body.
Members of the family share the same broad actions: they signal fullness, slow stomach emptying, and take part in blood sugar regulation.
List 1: Sorted by pathway
Single-pathway medications. These act on the GLP-1 receptor only. Semaglutide belongs to this group, along with several older medications in the class.
Dual-pathway medications. These act on two receptors, GLP-1 and GIP. Tirzepatide is in this group.
Investigational medications. Compounds that act on three pathways, and other new designs, are still being studied in clinical trials. They are not FDA-approved for any use.
List 2: Sorted by schedule
Once weekly. The more recent members of the family, including semaglutide and tirzepatide injections, are designed to last about a week.
Once daily. Some older injectable medications and the tablet forms are taken every day.
Twice daily. The earliest medications in the class required two injections a day and are seldom used for weight management now.
Schedule matters mostly for convenience and for how consistently a person can follow the plan.
List 3: Sorted by format
Injection under the skin. The most common format. Some come as pre-filled pens and others as a vial with a syringe.
Tablet. FDA-approved semaglutide exists as a swallowed tablet. Some services also prescribe compounded rapid-dissolve tablets, which are a different product and have not been reviewed by the FDA.
Format affects handling as well. Injections often need refrigeration and sharps disposal, while tablets do not.
List 4: Sorted by FDA status
This is the sorting that most affects what you are actually getting.
FDA-approved products. Brand-name medications that the FDA has reviewed for safety and effectiveness for specific uses. Some are approved for type 2 diabetes, some for chronic weight management, and some for both under different names.
Compounded versions. Prepared by state-licensed pharmacies for individual prescriptions. They are not FDA-approved, they are not generics, and they have not been reviewed by the FDA for safety, effectiveness, or quality. Rules on compounding these medications have been changing.
Unapproved products sold online. Vials marketed as "research use only" or "not for human consumption," and versions of investigational drugs that are still in trials. The FDA has warned against these. They are not prescribed, are not made under pharmacy standards, and should not be used.
Where the Nu Image options fit
Other members of the family exist as FDA-approved brand-name products. Nu Image does not offer those.
What the whole family has in common
- Prescription only. Every legitimate GLP-1 medication requires evaluation by a licensed provider.
- Gradual dosing. Treatment starts low and increases step by step.
- Similar side effects. Nausea, constipation, diarrhea, and a feeling of fullness are the most common.
- Shared precautions. FDA-approved products in this class carry a boxed warning about thyroid C-cell tumors seen in animal studies. They are not used in people with a personal or family history of medullary thyroid carcinoma or MEN 2, and they are not used during pregnancy.
Terms that are often confused
- GLP-1 and GLP-1 agonist. The first is the natural hormone, and the second is a medication that mimics it.
- Semaglutide and its brand names. Semaglutide is the active ingredient. Brand names refer to specific FDA-approved products that contain it.
- Compounded and generic. A generic is an FDA-approved copy of a brand-name drug. A compounded medication is not.
- GLP-1 and insulin. They are different medications, and one does not replace the other.
Questions to ask about any medication on the list
- Which pathway does it act on?
- How often is it taken, and in what format?
- Is it FDA-approved or compounded?
- Which pharmacy prepares it?
- Is it appropriate given my health history and other medications?
Talking with a provider
Nu Image offers online evaluations with licensed providers, who review your history and decide whether a prescription is appropriate. A provider can explain where each option sits in this family and which, if any, suits you.
This content is for educational purposes only and is not medical advice, diagnosis, or treatment. Compounded medications are prepared by state-licensed compounding pharmacies and are not reviewed or approved by the FDA for safety, efficacy, or quality. Prescription products require an online consultation with a licensed healthcare provider, who will determine whether a prescription is appropriate.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.
