How GLP-1 Medications Work
Understanding the science behind these revolutionary weight loss and diabetes medications.
What is GLP-1?
GLP-1 (glucagon-like peptide-1) is a hormone naturally produced in your gut after you eat. It plays a crucial role in regulating blood sugar levels and appetite. GLP-1 receptor agonists are medications that mimic this natural hormone, but in a more potent and longer-lasting form.
When you take a GLP-1 medication, it activates the same receptors in your body that natural GLP-1 does, but with enhanced and prolonged effects. This leads to better blood sugar control, reduced appetite, and significant weight loss in many patients.
The Mechanisms of Action
Brain & Appetite Control
GLP-1 medications act on receptors in the brain's appetite control centers, particularly the hypothalamus. This reduces hunger signals and increases feelings of fullness (satiety). Many users report a dramatic reduction in food cravings and "food noise" - the constant thoughts about food.
Slowed Gastric Emptying
These medications slow down how quickly food leaves your stomach. This means you feel full longer after eating smaller portions. While this contributes to weight loss, it's also why some people experience nausea, especially when first starting treatment or after dose increases.
Pancreas & Insulin
GLP-1 medications stimulate insulin release from the pancreas when blood sugar is high. Importantly, they do this in a glucose-dependent manner, meaning they only increase insulin when it's needed. This reduces the risk of hypoglycemia (low blood sugar) compared to some other diabetes medications.
Liver & Glucagon
These medications also reduce the release of glucagon, a hormone that signals the liver to release stored sugar into the bloodstream. By lowering glucagon levels, GLP-1 medications help prevent blood sugar spikes between meals and overnight.
Types of GLP-1 Medications
Semaglutide (Ozempic, Wegovy, Rybelsus)
Semaglutide is one of the most studied and popular GLP-1 medications. Ozempic is approved for Type 2 diabetes, while Wegovy (a higher dose) is approved specifically for weight loss. Rybelsus is the first and only oral GLP-1 medication, offering an alternative to injections.
Tirzepatide (Mounjaro, Zepbound)
Tirzepatide is a dual GIP/GLP-1 receptor agonist, meaning it activates two different hormone pathways. This dual action has shown even greater weight loss results in clinical trials. Mounjaro is approved for diabetes, while Zepbound is approved for weight management.
Liraglutide (Saxenda, Victoza)
Liraglutide was one of the first GLP-1 medications and requires daily injections. While effective, the daily dosing schedule is less convenient than newer weekly options. Victoza is used for diabetes, while Saxenda is the weight loss formulation.
Dulaglutide (Trulicity)
Dulaglutide is a weekly GLP-1 medication primarily used for Type 2 diabetes management. It offers convenient weekly dosing and has shown cardiovascular benefits. Weight loss is typically more modest compared to semaglutide or tirzepatide.
What to Expect When Starting
Titration Period (Weeks 1-8)
You'll start on a low dose and gradually increase over several weeks. This helps minimize side effects as your body adjusts. Nausea and GI symptoms are most common during this phase but typically improve with time.
Appetite Changes (Weeks 2-4)
Many people notice reduced appetite and fewer food cravings within the first few weeks. You may find yourself satisfied with smaller portions and less interested in snacking or overeating.
Weight Loss Begins (Weeks 4-12)
Noticeable weight loss typically begins within the first month and continues steadily. Most people see the majority of their weight loss within the first 12-18 months of treatment.
Maintenance Phase (Ongoing)
Once you reach your target dose and weight loss goals, you'll continue the medication to maintain results. Studies show that stopping the medication often leads to weight regain, so long-term use is typically recommended.
Ready to Compare Medications?
Now that you understand how GLP-1 medications work, compare the different options to find what might be right for you.