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By now everyone knows that GLP-1s have something to do with weight loss, but what is a GLP-1 drug, really? And how do they actually work?
If you’ve ever wondered about the science of GLP-1s, this article is for you.
A brief history of GLP-1s
GLP-1 receptor agonists were originally developed to treat type 2 diabetes. Over time, researchers noticed a remarkable “side effect”: significant weight loss.
Today, these medications are reshaping how the medical world approaches obesity and metabolic health.
What is a GLP-1? The science made simple
GLP-1 stands for glucagon-like peptide-1, which is a hormone the body naturally produces after you eat.
GLP-1 has several important jobs:
- Signals your pancreas to release insulin, which lowers blood sugar
- Suppresses glucagon, a hormone that raises blood sugar
- Slows down gastric emptying, meaning food moves more slowly from your stomach to the intestines
- Sends appetite signals to the brain, triggering feelings of fullness and reducing appetite
Natural GLP-1 breaks down in the body within just a few minutes, so its effects are temporary.
👉 Learn more: 7 ways to support your body’s natural GLP-1 production
How GLP-1 medications work
GLP-1 receptor agonists are engineered to mimic the GLP-1 hormone—but the effects last much longer. With more blood sugar support, increased fullness, and slowed digestion, it gets a lot easier to reduce your overall calorie intake.
The result, for many, is meaningful weight loss, even if they haven’t been able to lose weight—and keep it off—through traditional methods alone (i.e., diet and exercise). GLP-1s are designed to work with the body’s natural appetite signals, not against them, so people don’t have to rely on an inexhaustible supply of willpower (which none of us have) to maintain the weight they want.
GLP-1 vs. GIP: Understanding the difference
You may have noticed another acronym alongside GLP-1 lately: GIP. Like GLP-1, GIP (glucose-dependent insulinotropic polypeptide) is an incretin hormone, meaning it is released from the gut after eating and helps the body manage blood sugar by stimulating insulin release.
GIP is actually the more abundant of the two incretins, but was historically thought to play only a modest role in weight regulation. However, this understanding has shifted significantly with the development of one of the newer GLP-1 agonists: tirzepatide.
How GLP-1 and GIP differ
While GLP-1 and GIP share some overlapping functions, they work through distinct receptors and have different effects across the body:
- GLP-1 is a potent appetite suppressant. It slows gastric emptying, reduces food intake, and directly acts on brain regions that regulate hunger and reward. It also lowers glucagon levels, which helps keep blood sugar from spiking after meals.
- GIP also stimulates insulin secretion, but its influence extends further into fat metabolism. GIP receptors are found in fat tissue, and activation appears to improve how the body stores and processes fat.
Targeting both receptors appears to produce additive effects on blood sugar control and weight loss. (Learn more about the first major head-to-head study of GLP-1 vs. GLP-1 + GIP agonists here.) That being said, the best medication type will vary from person to person, with some responding to one better than the other.
What this means for weight management and metabolic health
The weight-loss effects of GLP-1 medications come from several mechanisms working together.
Appetite suppression: GLP-1 receptors are found in the brain regions that regulate hunger. When activated, these receptors reduce appetite and make it easier to eat less without feeling deprived.
Slower gastric emptying: By slowing how quickly your stomach empties, food stays in the digestive system longer. This helps you feel full for longer and can also reduce how much you eat.
Reduced food noise: Constant, intrusive thoughts about food can take up a lot of brain space and ramp up cravings and emotional eating urges. Some have reported that GLP-1s help quiet that food noise, freeing them to focus on other things simply because they’re not thinking about food all the time.
Biology, not motivation: Obesity is a complex, chronic condition with hormonal and neurological components, and it requires long-term treatment to manage it effectively. GLP-1s have emerged as a tool that can address the biological drivers of hunger and weight management—because for many, lifestyle changes alone are not enough to keep weight in a healthy range.
Why lifestyle still matters
GLP-1s are a helpful tool for weight management, but they are not a standalone solution to weight loss. Those who incorporate lifestyle changes alongside medication typically see better results and are more likely to maintain the weight they want long term.
The “usual” recommendations still apply, which includes a balanced, nutritious diet and regular exercise. For GLP-1 users, the following habits are especially important to develop:
- Prioritize protein. When you lose weight, you’re probably losing muscle mass too. Consuming more protein is one way to help preserve lean muscle mass during your weight-loss journey.
- Incorporate strength training. Protein and strength training work hand-in-hand to preserve and build muscle mass. 2–3 sessions per week is about all you need to protect muscle while on a GLP-1.
- Hydrate regularly. GLP-1 treatments can be dehydrating, whether it’s because of side effects like diarrhea or because you’re just not eating as much. Water helps keep each system of the body working optimally, so make sure you’re using that water bottle you’re lugging around as more than just emotional support.
The weight-loss and diet industry has often been associated with extremes, even though research and real-life experience have shown again and again that restrictive diets and intense exercise regimens aren’t sustainable. GLP-1s are meant to help you actually maintain healthy habits—and keep the weight off, too.
GLP-1 medications available
Several GLP-1 drugs are currently on the market, though they are approved for different uses.
GLP-1s FDA-approved for weight management:
- Wegovy® (semaglutide)
- Zepbound ® (tirzepatide)
- Saxenda (liraglutide)
Ozempic® (semaglutide) and Mounjaro® (tirzepatide) are FDA-approved for type 2 diabetes, but may sometimes be prescribed off-label for weight management if deemed appropriate by a medical provider.
Qualification for each of these medications is determined by BMI and medical history and requires a prescription from a licensed healthcare provider.
A note on compounded GLP-1s
Due to high demand, compounded versions of semaglutide and tirzepatide may be recommended. These drugs are not FDA-approved and should be taken only under the guidance of a licensed provider.*
Common GLP-1 side effects
The most frequently reported side effects are gastrointestinal and are usually most pronounced at the start of treatment or after increasing the dose. These include:
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Abdominal discomfort
If side effects persist or are severe, reach out to your medical provider. Learn more about potential GLP-1 side effects—and how to manage them—here.
Frequently asked questions about GLP-1s
Will I gain the weight back if I stop GLP-1 treatment?
Many people do. Obesity is a chronic condition that requires long-term treatment; like treatment for any other long-term condition, the benefits cease when treatment stops. That being said, those who incorporate healthy and sustainable lifestyle changes are more likely to keep at least some of the weight off if they discontinue GLP-1 medication.
Are GLP-1s safe for long-term use?
GLP-1 medications are generally considered safe for long-term use when prescribed and monitored by a healthcare provider. In fact, several GLP-1s were originally developed for conditions like type 2 diabetes, which means they were studied with long-term treatment in mind. Furthermore, discontinuing treatment may reverse the benefits you have gained, which may pose greater risks than taking the medication long term.
Isn’t taking a GLP-1 cheating?
No. This assumption frames obesity as a character flaw rather than a biologically driven medical condition. GLP-1s help correct biological dysregulation in the same way insulin helps a diabetic or statins helps someone with high cholesterol. Using medications as prescribed is not a shortcut; it’s simply treating a condition with the best tools available.
Will I lose muscle mass while on a GLP-1?
Rapid weight loss from any cause can cause the loss of lean muscle mass. This is why providers often recommend combining GLP-1 therapy with adequate protein intake and regular resistance exercises to help preserve muscle.
The bigger picture
GLP-1s are about more than just finally getting the body you always wanted. They are a tool that can help improve a variety of metabolic health issues, from insulin sensitivity to heart health. For many, GLP-1s make it possible to focus on whole-body health rather than just one metric, like the number on the scale.
If you’re curious about whether GLP-1 therapy is right for you, visit tryshed.com today to see if you qualify.
This information is for educational purposes only and is not a substitute for medical advice. Please consult your healthcare provider before starting or changing any medication.
Compounded medications are prepared by licensed pharmacies to meet the specific needs of individual patients. These medications are not reviewed or approved by the FDA for safety, effectiveness, or quality. However, they are made in accordance with strict regulatory guidelines. If your clinician determines that a compounded medication is clinically appropriate for you, please be aware that it is not an FDA-approved product.
