Is your medication a GLP-1? Brands, molecules, and drug classes

Zepbound, Mounjaro, Wegovy, and Ozempic are among the most widely prescribed weight management and diabetes medications in the United States. Yet each belongs to a distinct molecular class, with different mechanisms of action, approved indications, and safety profiles.

The question of whether a specific medication is a GLP-1 carries direct clinical weight. The answer determines how the drug works, which conditions it can treat, and how it must be managed alongside other therapies.

This reference maps each major brand name to its active molecule and drug class, including the newest entrant, Foundayo (orforglipron), an oral GLP-1 receptor agonist approved by the FDA in 2026. The following sections provide a structured breakdown of the current landscape, from single-action glucagon-like peptide-1 receptor agonists to the dual-action GIP/GLP-1 class.

Key Takeaways

• Zepbound and Mounjaro contain tirzepatide, a dual-action molecule that targets both the GLP-1 and GIP receptors simultaneously. Tirzepatide acts on the GLP-1 receptor, but it is not a pure GLP-1 medication.
• Wegovy, Ozempic, Rybelsus, and Saxenda are GLP-1 receptor agonists, though they differ in active molecule, delivery method, and approved indication.
• Foundayo (orforglipron) is an oral GLP-1 receptor agonist approved by the FDA in 2026 and taken once daily with or without food.
• Gastrointestinal side effects from tirzepatide are dose-dependent. Per the Zepbound label, nausea occurred in 25% of patients at 5 mg, 29% at 10 mg and 28% at 15 mg, compared with 8% on placebo.
• Combining Zepbound with Mounjaro or any GLP-1 agonist duplicates therapy and must be avoided.

What Does "GLP-1" Mean? (Brief Explanation of Class)

GLP-1 stands for glucagon-like peptide-1 receptor agonist, a class of medications that mimic a hormone the body produces naturally to regulate hunger and blood sugar. These drugs signal the brain to feel fuller sooner and reduce the drive to eat.

Prescribers recommend GLP-1 receptor agonists for adults with obesity, or overweight status combined with at least one weight-related health condition. They are also used for type 2 diabetes management and, in certain formulations, for cardiovascular risk reduction in adults with established heart disease.

Brand Examples and Delivery Methods

Most GLP-1 medications are injectable. Wegovy, Ozempic, and Saxenda all use prefilled injection pens. Rybelsus delivers semaglutide as an oral tablet, taken once daily for type 2 diabetes. Wegovy and Ozempic both contain semaglutide, a GLP-1 receptor agonist developed by Novo Nordisk. Saxenda contains liraglutide, a separate GLP-1 molecule, also from Novo Nordisk.

All of these medications are available by prescription only and are not controlled substances. A prescriber will assess which option fits an individual health profile.

The Thyroid Cancer Warning: Specific Context Matters

Some medications in this class, including Zepbound, carry a boxed warning related to thyroid C-cell tumors. This warning is based on rodent studies, not human data.

According to the FDA-approved prescribing information for Zepbound, the drug is contraindicated specifically for patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). It is not a blanket restriction for the general population. A prescriber reviews personal and family medical history before starting treatment to assess whether this contraindication applies.

Brand to Molecule Mapping (Zepbound, Mounjaro, Wegovy, Ozempic, and More)

Each brand name corresponds to a specific active molecule. Understanding this mapping clarifies why two brands can be chemically identical, and why combining certain medications creates serious therapeutic overlap.

1. Zepbound delivers tirzepatide as its active ingredient, available through injection using single-dose vials or single-dose pens.
2. Mounjaro also contains tirzepatide, making it chemically identical to Zepbound. The two products are approved for different diagnoses. A prescriber determines which is appropriate based on treatment goals.
3. Wegovy carries semaglutide as its active molecule, administered by weekly injection for chronic weight management.
4. Ozempic also contains semaglutide but is approved primarily for type 2 diabetes management rather than obesity treatment.
5. Rybelsus delivers semaglutide in oral tablet form, taken once daily. It is approved for blood sugar control in adults with type 2 diabetes.
6. Saxenda uses liraglutide as its active ingredient, delivered by daily injection. It is a distinct molecule from semaglutide, though both are classified as GLP-1 receptor agonists.
7. Foundayo contains orforglipron, a once-daily oral GLP-1 receptor agonist approved by the FDA in 2026. Its label allows it to be taken with or without food, which sets it apart from Rybelsus (oral semaglutide), whose label requires an empty stomach and a wait before eating or drinking.

Zepbound remains available only as a brand-name product. No generic alternatives are currently on the market.

Classifying Each Molecule: GLP-1, GIP, or Dual-Action?

The table below maps every current major brand to its active molecule and drug classification. This structure is the foundation of any informed conversation between a patient and their prescriber about weight management or diabetes treatment.

The Core Distinction: Single-Action vs. Dual-Action

Semaglutide and liraglutide are single-action GLP-1 agonists. Each targets the GLP-1 receptor through one pathway. Wegovy, Ozempic, and Rybelsus all deliver semaglutide. Saxenda delivers liraglutide. Foundayo delivers orforglipron, a structurally distinct small-molecule agent that also targets the GLP-1 receptor, but through an oral formulation that requires no food or water restrictions.

Tirzepatide is different. It activates both the GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors simultaneously. Zepbound and Mounjaro both contain tirzepatide. This dual-action mechanism separates tirzepatide from the single-receptor GLP-1 molecules and is why it is classified as a dual GIP/GLP-1 receptor agonist rather than a pure GLP-1.

Duplicate Therapy: A Real Prescribing Risk

Combining Zepbound with Mounjaro, or adding any GLP-1 agonist to a tirzepatide regimen, duplicates therapy. Both products target the same receptor or contain the same molecule, creating unnecessary clinical risk. Active prescriber review of all current medications before starting tirzepatide remains a critical safety step.

How These Medications Work: Mechanisms of Action

The body uses hormones called incretins to regulate hunger and blood sugar after meals. GLP-1 receptor agonists mimic these natural signals, reducing appetite and slowing the rate at which the stomach empties.

Zepbound copies two incretins at once: GLP-1 and GIP. Injected once weekly, it signals the brain to suppress appetite, supports fat metabolism, and improves insulin sensitivity. This dual-receptor engagement distinguishes tirzepatide from semaglutide, which works through the GLP-1 pathway alone.

Side Effects and Dose Dependency

Gastrointestinal side effects are the most common during treatment. They typically occur as the digestive system adjusts to the new hormone signals and are most pronounced during dose titration.

Per the Zepbound FDA label's pooled adverse-reaction data, nausea affects roughly 25 to 29 percent of tirzepatide users, diarrhea 19 to 23 percent, constipation 11 to 17 percent, and vomiting 8 to 13 percent. In the pivotal SURMOUNT-1 trial, published in The New England Journal of Medicine, mean weight change at week 72 was -15.0% on 5 mg, -19.5% on 10 mg and -20.9% on 15 mg, compared with -3.1% on placebo. Vomiting followed a similar pattern, rising from 8.3% at 5 mg to 12.2% at 15 mg, versus 1.7% on placebo.

This pattern has practical implications. Patients titrating from 5 mg toward the 15 mg maintenance dose should anticipate that GI symptoms may intensify before stabilizing. Discussing pacing strategies with a prescriber before a dose increase is a prudent step.

Drug Interactions to Know

Combining tirzepatide or any GLP-1 agonist with insulin raises the risk of dangerously low blood sugar. A prescriber must review the full medication list before treatment begins.

Per the Zepbound FDA label, tirzepatide can reduce the effectiveness of oral hormonal contraceptives. Patients using oral contraceptives are advised to switch to a non-oral method, or add a barrier method, for four weeks after starting treatment and for four weeks after each dose increase.

Key Differences Between Single and Dual-Action Drugs

Single-action and dual-action medications work through different biological pathways. The table below compares these two drug classes across the factors most relevant to prescribing decisions and patient experience.

Zepbound's sleep apnea indication carries specific eligibility criteria. According to the FDA's press announcement, "FDA Approves First Medication for Obstructive Sleep Apnea", the approval covers moderate to severe obstructive sleep apnea in adults with obesity. It was based on two 52-week randomized, placebo-controlled trials in 469 adults without type 2 diabetes, one enrolling participants using positive airway pressure therapy and one enrolling those unable or unwilling to use it. Patients who do not meet both the BMI and AHI thresholds are not candidates for this specific indication.

Summary Table: Brand to Molecule to Drug Class Map

The table below consolidates the current landscape into a single reference. It reflects the class structure as of 2026, including Foundayo as the newest approved product in this category.

Zepbound and Mounjaro are the only current products in the dual-action class. All other brands in the table target the GLP-1 receptor pathway alone. They differ by active molecule, delivery format, and approved indication, but they share the same fundamental classification as GLP-1 receptor agonists.

This map is a reference tool, not a prescribing guide. A healthcare provider is the appropriate authority for matching a specific medication to an individual clinical profile, medical history, and treatment goals.

FAQs

1. Is Ozempic a GLP-1?

Yes. Ozempic is a GLP-1 receptor agonist containing semaglutide, made by Novo Nordisk and FDA-approved for type 2 diabetes in 2017.

2. Is Mounjaro a GLP-1?

Mounjaro is a dual GIP and GLP-1 receptor agonist containing tirzepatide, made by Eli Lilly. It acts on the GLP-1 receptor but is not a pure GLP-1 medication. In the SURMOUNT-1 trial, tirzepatide produced up to 22.5% mean weight reduction at the 15 mg dose.

3. Is Wegovy a GLP-1?

Yes. Wegovy is a GLP-1 receptor agonist that uses a higher dose of semaglutide than Ozempic and is approved for chronic weight management.

4. What risks come with GLP-1 drugs like Ozempic and Wegovy?

These medications carry a boxed warning for thyroid C-cell tumors and are contraindicated in people with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Always consult a licensed healthcare provider before treatment.

5. Are there new GLP-1 options coming?

The newest approved option is Foundayo (orforglipron), an oral GLP-1 receptor agonist approved by the FDA on April 1, 2026 for chronic weight management. It is the only GLP-1 pill that can be taken any time of day without food or water restrictions.