What is a GLP-1? The Hormone Behind Weight Loss Drugs

Quick Answer

What is a GLP-1? GLP-1, or glucagon-like peptide-1, is a hormone your gut releases after you eat that controls appetite and blood sugar. GLP-1 medications copy this hormone to treat type 2 diabetes and obesity. Common GLP-1 drugs include semaglutide, sold as Ozempic and Wegovy, and tirzepatide.

Key Takeaways

• A GLP-1 is both a natural gut hormone and a class of medications that copy it.
• GLP-1 stands for glucagon-like peptide-1, released after you eat to control appetite and blood sugar.
• GLP-1 medications include semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).
• About 18 percent of US adults have taken a GLP-1 drug, per a 2025 KFF poll.
• GLP-1 medications are prescription-only and require a provider evaluation.

What is a GLP-1, in plain terms?

What is a GLP-1? The term means two things. First, a GLP-1 is a natural hormone your gut releases after a meal. Second, a GLP-1 is a class of medications built to copy that hormone. The full name is glucagon-like peptide-1.

The natural hormone fades within minutes. A GLP-1 medication makes the same signal last much longer, often a full week. That is the core idea behind drugs like semaglutide and tirzepatide.

What does a GLP-1 do in the body?

A GLP-1 works in several places at once. It acts on the pancreas, the stomach, and the brain. Together these effects steady blood sugar and reduce hunger. Here is what happens after the hormone, or the medication, goes to work.

• It prompts the pancreas to release insulin when blood sugar is high.
• It lowers glucagon, a hormone that raises blood sugar.
• It slows how fast the stomach empties, so meals feel filling for longer.
• It acts on appetite centers in the brain, so hunger drops.

The appetite effects are why GLP-1 medications help with weight. People eat less without constant hunger. To keep muscle while losing fat, aim for enough protein. The AHC GLP-1 protein calculator gives you a daily target.

Where does GLP-1 come from in the body?

Part of what is a GLP-1 is understanding where it is made. Special cells in your gut, called L-cells, release GLP-1 after you eat. They sense protein, fat, carbohydrate, and fiber moving through the intestine and respond by sending out the hormone.

Natural GLP-1 is short-lived. An enzyme called DPP-4 breaks it down within minutes, so the natural signal fades fast. In people with obesity, the response after eating can also be blunted. That gap is what a GLP-1 medication fills, by making the same signal last about a week.

How can you increase GLP-1 naturally?

Another part of what is a GLP-1 is how to support it. You cannot match a medication with food alone, but several habits support your body’s own GLP-1. The evidence points to a few consistent levers.

• Fiber: build meals around oats, barley, legumes, and vegetables. Fermentable fibers like inulin and oligofructose are especially helpful.
• Protein: eggs, fish, lean meat, and yogurt raise GLP-1 after meals and help you feel full.
• Healthy fats: avocado, nuts, and olive oil support the hormone’s release.
• Fermented foods: yogurt, kefir, and similar foods feed a gut microbiome that supports GLP-1.
• Exercise: moderate to high intensity activity, around 150 minutes a week, can raise GLP-1.
• Sleep and stress: poor sleep and high stress can blunt the response, so both matter.

These habits help, but the effect is modest and short-lived next to medication. For significant weight loss, a GLP-1 medication provides a stronger, longer signal.

Is there a natural Ozempic?

Social media often calls a food or supplement a natural Ozempic. Berberine is the most common example. The honest answer is that no food or supplement matches a prescription GLP-1. Research on berberine, psyllium, and similar supplements is limited, much of it from animal or lab studies.

Understanding what is a GLP-1 makes this clearer. Fiber, protein, and exercise genuinely nudge your own GLP-1, which is worth doing. They are not a replacement for medication when a provider decides one is appropriate.

What is a GLP-1 receptor agonist?

A GLP-1 receptor agonist is the technical name for these medications. An agonist is a drug that switches on a receptor. So a GLP-1 receptor agonist switches on the same receptors the natural GLP-1 hormone uses. Semaglutide is one example. The NIH lists semaglutide as approved across three brands.

What GLP-1 medications are available?

Several GLP-1 medications are on the market, each with its own brands and uses. Some act on GLP-1 alone. Tirzepatide acts on two hormones, GLP-1 and GIP, which is covered below.

What is a GLP-1 used for?

Another part of what is a GLP-1 is its range of uses. GLP-1 medications have grown beyond diabetes. The FDA first approved this class for type 2 diabetes, then for chronic weight management, and more recently to lower cardiovascular risk in certain adults. Use has climbed fast. A 2025 KFF poll found that about 18 percent of US adults have taken a GLP-1 drug, and prescriptions have more than tripled since 2020.

• Type 2 diabetes, to improve blood sugar control.
• Chronic weight management, for adults with obesity or related conditions.

Cardiovascular risk reduction, for certain adults with heart disease.

How effective are GLP-1 medications for weight loss?

A common part of what is a GLP-1 is how well it works. Results vary, and they depend on the specific drug. In the NEJM STEP 1 trial, semaglutide produced about 14.9 percent mean weight loss over 68 weeks. The dual-hormone drug tirzepatide has gone further, up to about 20.9 percent in its trials. Both work best alongside diet and activity.

To set a realistic pace for your own goal, map your timeline with the AHC weight loss planner.

What are the side effects of GLP-1 medications?

Most side effects involve the gut, because a GLP-1 slows digestion. Nausea, diarrhea, constipation, and stomach discomfort are the most common. In the STEP 1 trial, nausea affected about 44 percent of the semaglutide group, though most cases were mild to moderate and eased over time.

• Nausea, vomiting, diarrhea, or constipation, especially when starting or raising the dose.
• Stomach pain, bloating, or burping.
• Lower appetite and feeling full quickly.

FDA labels for these drugs carry a boxed warning. In animal studies they caused thyroid C-cell tumors, and whether they do so in humans is not known. People with a personal or family history of medullary thyroid carcinoma or MEN 2 should not use them.

Who should not take a GLP-1 medication?

A GLP-1 medication is not right for everyone. A provider screens for these situations before prescribing any GLP-1, brand or compounded.

• A personal or family history of medullary thyroid carcinoma or MEN 2.
• A known allergy to the drug or any ingredient in the product.
• Pregnancy, plans to become pregnant, or breastfeeding.
• A history of pancreatitis or certain serious gastrointestinal conditions.

What is the difference between a GLP-1 and a GLP-1/GIP drug?

A standard GLP-1 medication, like semaglutide, acts on one hormone pathway. Tirzepatide acts on two: GLP-1 and GIP, another gut hormone. Hitting both pathways has produced larger weight loss in trials. A provider helps decide which fits your situation and health history.

Where did GLP-1 medications come from?

Part of what is a GLP-1 is its short history. The drug class is newer than it seems. The first GLP-1 receptor agonist, exenatide, reached the market in the mid-2000s. Liraglutide and dulaglutide followed, then semaglutide, and most recently the dual GLP-1 and GIP drug tirzepatide. Each generation has aimed for stronger effects and easier dosing.

The next wave is already in trials, including triple-hormone drugs such as retatrutide. A provider can explain which approved GLP-1 medications fit your situation today.

What is a compounded GLP-1 medication?

A compounded GLP-1 is a version prepared by a licensed pharmacy from the active ingredient, based on a prescription for one specific patient. Compounded GLP-1 medications are not FDA-approved. The FDA notes that compounded drugs are not reviewed for safety, effectiveness, or quality before they reach patients.

With an approved brand, you get a standardized, FDA-reviewed product. With a compounded GLP-1, you rely on the licensed provider who prescribes it and the licensed pharmacy that prepares it. Once you have a supply, the AHC guide on how to store compounded semaglutide helps keep it stable.

Is a compounded GLP-1 legal in 2026?

The rules shifted recently. Pharmacies could compound copies while semaglutide and tirzepatide sat on the FDA shortage list. Once those shortages resolved, that allowance closed. The timeline below shows where things stand.

1. Late 2024 to early 2025: the FDA declared the tirzepatide and semaglutide shortages resolved.
2. Spring 2025: the enforcement grace periods for 503A pharmacies and 503B outsourcing facilities ended.
3. April 30, 2026: the FDA proposed removing semaglutide and tirzepatide from the 503B bulk substances list, with a comment window closing June 29, 2026.

Patient-specific compounding under section 503A continues under its own framework when a licensed provider documents a clinical need. A provider decides what is appropriate, case by case.

How do you start a GLP-1 program?

Every GLP-1 medication is prescription-only. You cannot buy one over the counter. The path is simple, and it starts with a quick check of your numbers.

Begin with the AHC BMI calculator to see if you are in range, then take the evaluation so a licensed provider can review your history and goals.

Frequently Asked Questions

What is a GLP-1?

What is a GLP-1 in one sentence? A GLP-1 is a gut hormone called glucagon-like peptide-1, and also a class of medications that copy it to treat diabetes and obesity.

What does GLP-1 stand for?

GLP-1 stands for glucagon-like peptide-1. It is a hormone your gut releases after eating that helps control appetite and blood sugar.

What are examples of GLP-1 medications?

Common GLP-1 medications include semaglutide (Ozempic, Wegovy, Rybelsus), tirzepatide (Mounjaro, Zepbound), liraglutide (Victoza, Saxenda), and dulaglutide (Trulicity).

What is a GLP-1 used for?

GLP-1 medications are used for type 2 diabetes, chronic weight management, and to reduce cardiovascular risk in certain adults. A provider decides which use applies.

How does a GLP-1 help with weight loss?

A GLP-1 slows stomach emptying and acts on appetite centers in the brain, so you feel full sooner and eat less. That supports weight loss alongside lifestyle changes.

Is semaglutide a GLP-1?

Yes. Semaglutide is a GLP-1 receptor agonist, one of the most widely used GLP-1 medications. It is sold as Ozempic, Wegovy, and Rybelsus.

Is tirzepatide a GLP-1?

Tirzepatide acts on the GLP-1 pathway and also on GIP, a second gut hormone. It is often grouped with GLP-1 drugs but is technically a dual agonist.

Are GLP-1 medications safe?

FDA-approved GLP-1 drugs have known safety profiles with risks on their labels, including a boxed warning. Compounded versions are not FDA-approved. Discuss your history with a licensed provider.

What are the side effects of a GLP-1?

Gastrointestinal effects lead the list: nausea, diarrhea, constipation, and stomach discomfort. Most are mild to moderate and ease over time as the body adjusts.

How many people take GLP-1 drugs?

A 2025 KFF poll found about 18 percent of US adults have taken a GLP-1 drug, and prescriptions have more than tripled since 2020.

Do you need a prescription for a GLP-1?

Yes. Every GLP-1 medication is prescription-only. A licensed provider must evaluate you before prescribing one.

What is a compounded GLP-1?

It is a GLP-1 prepared by a licensed pharmacy from an individual prescription. Compounded GLP-1 medications are not FDA-approved and are not reviewed by the FDA for safety or quality.

Is a compounded GLP-1 legal in 2026?

Mass-scale compounding of copies ended after the shortages resolved. Patient-specific compounding under section 503A continues when a licensed provider documents a clinical need.

Which GLP-1 is best for weight loss?

It depends on the person. Tirzepatide has shown larger weight loss in trials, but the right choice depends on your health history and a provider’s judgment.

What is a GLP-1 agonist?

What is a GLP-1 agonist? It is a medication that switches on GLP-1 receptors, copying the natural hormone. Semaglutide and liraglutide are GLP-1 agonists.

What is a GLP-1 prescribed for?

What is a GLP-1 prescribed for? Mainly type 2 diabetes and chronic weight management, and in some cases to lower cardiovascular risk. A provider decides which use applies.

What is a GLP-1 microdose?

What is a GLP-1 microdose? It is a smaller-than-standard amount, sometimes used to ease side effects or maintain weight, always under provider guidance.

What is a GLP-1’s main side effect?

What is a GLP-1‘s main side effect? Gastrointestinal upset, especially nausea, leads the list. Most cases are mild to moderate and ease as the body adjusts.

What is a GLP-1 made from?

What is a GLP-1 made from? The medications are synthetic peptides designed to mimic the natural glucagon-like peptide-1 hormone your gut produces.

How can I increase GLP-1 naturally?

Fiber-rich foods, protein, healthy fats, fermented foods, regular exercise, and good sleep all support your body’s own GLP-1. The effect is modest compared with medication.

What foods boost GLP-1?

High-fiber foods like oats, barley, and legumes, plus protein and healthy fats such as avocado and nuts, help trigger GLP-1 release after meals.

Is berberine a natural GLP-1?

Berberine is often called nature’s Ozempic, but the evidence is limited and it does not match a prescription GLP-1. Talk to a provider before relying on supplements.

Where is GLP-1 produced in the body?

GLP-1 is made by L-cells in your small intestine and released after you eat, in response to protein, fat, carbohydrate, and fiber.

What was the first GLP-1 drug?

Exenatide was the first GLP-1 receptor agonist. Liraglutide, dulaglutide, semaglutide, and the dual agonist tirzepatide followed.

How do I find out if a GLP-1 is right for me?

Take the AHC free online evaluation. A licensed U.S. provider reviews your answers and decides what is appropriate before any treatment ships.

Start with Alternate Health Club

Alternate Health Club is a LegitScript-certified telehealth platform. Want to know if a compounded GLP-1 program fits your situation? Take the free online evaluation. Independently licensed U.S. providers review every assessment, and approved treatment ships to all 50 states at flat monthly pricing, with no membership fees and no dose-escalation markups.

Medical disclaimer

This article is for educational purposes only and is not medical advice. It does not create a doctor-patient relationship. Compounded medications referenced here are not FDA-approved and have not been reviewed by the FDA for safety, effectiveness, or quality. Prescriptions are issued only by independently licensed U.S. clinicians after an individual evaluation, and providers retain full discretion to prescribe or decline treatment. Results vary by individual. Brand names belong to their respective trademark owners and are used only for educational context. Always talk with a licensed healthcare professional before starting, stopping, or changing any medication.