Over the past few years, GLP-1 medications have become a frequent topic of conversation around weight loss and weight management. Many people recognize brand names like Ozempic®, Wegovy®, Mounjaro® or Zepbound®, but still have questions about what these medications are, how they work, and why they are prescribed for both diabetes and obesity.
GLP-1 medications represent a shift in how weight is medically treated— toward a better understanding of how the body regulates appetite, metabolism and blood sugar.
This article explains how GLP-1 medications work, what benefits and risks to consider, and what patients should know before starting treatment.
How GLP-1 Medications Work for Weight Loss
To understand GLP-1 medications, it helps to first learn how the body naturally controls hunger and blood sugar.
What Are GLP-1 Medications?
GLP-1 stands for glucagon-like peptide-1, a hormone released by the intestines after eating.
This hormone plays an important role in:
- Signaling fullness to the brain
- Slowing digestion
- Helping the pancreas release insulin to regulate blood sugar
GLP-1 receptor agonists are medications designed to mimic this hormone. They were originally developed to treat type 2 diabetes, but clinicians observed that many patients also experienced significant weight loss.
How GLP-1 Medications Affect Appetite and Blood Sugar
GLP-1 medications work by strengthening the body’s natural signals related to hunger and metabolism.
Specifically, GLP-1 medications:
- Slow stomach emptying, helping people feel full sooner and stay full longer
- Reduce appetite and food cravings by acting on areas of the brain involved in hunger and satiety
- Support blood sugar control by improving insulin release after meals and reducing excess sugar production by the liver
Together, these effects make it easier for many people to eat smaller portions, feel satisfied and maintain healthier habits over time.
Common GLP-1 Medications and How They Differ
Many GLP-1 medications share similar ingredients, but they are approved by the U.S. Food and Drug Administration (FDA) for different uses.
Semaglutide, Ozempic® and Wegovy®
- Semaglutide is the active ingredient in both Ozempic® and Wegovy®
- Ozempic® is approved to treat type 2 diabetes
- Wegovy® contains higher doses of semaglutide and is approved specifically for weight loss
Other GLP-1 Options
- Liraglutide (Saxenda®) is a daily injection approved for weight loss
- Tirzepatide (Zepbound®, Mounjaro®) is a newer medication that targets two hormones (GLP-1 and GIP) and has shown even greater weight loss in clinical trials.
- Mounjaro® is approved for the management of type 2 diabetes, while Zepbound® and Saxenda®) are approved specifically for weight loss.
Although these medications work in similar ways, dosing, approval and insurance coverage vary.
How Effective Are GLP-1 Weight Loss Medications?
Clinical studies show that GLP-1 medications can lead to meaningful and sustained weight loss, especially when used as part of a comprehensive medical weight management program.
On average:
- Semaglutide is associated with about 15 percent body weight loss
- Liraglutide leads to 5-10 percent weight loss
- Tirzepatide has resulted in up to 20 percent weight loss in some studies
Key points to remember:
- Research suggests that patients with type 2 diabetes lose on average almost half of the weight loss that is seen for patients without diabetes, in the range of 5-12 percent of their initial weight.
- Real world studies released after these medications were approved illustrate high variability in the results, with 8-15 percent average weight loss for all medications.
Individual results vary, and these medications work best when combined with nutritional guidance, physical activity and ongoing medical care.
Other Health Conditions Treated With GLP-1 Medications
In addition to weight loss and diabetes management, GLP-1 medications may improve several conditions commonly linked to obesity and metabolic dysfunction.
These include:
- Prediabetes
- High blood pressure
- High cholesterol
- Atherosclerotic cardiovascular disease
- Osteoarthritis
- Fatty liver disease
- Polycystic ovary syndrome (PCOS)
- Obstructive sleep apnea
- Inflammatory states
Research is ongoing to better understand the potential benefits of GLP-1 medications for heart disease, kidney disease and inflammation-related conditions.
Side Effects of GLP-1 Medications: What to Expect
Like all medications, GLP-1 drugs can cause side effects. Most are related to digestion and tend to occur early in treatment or after dose increases.
Common GLP-1 side effects include:
- Nausea
- Vomiting
- Diarrhea or constipation
- Abdominal discomfort
- Fatigue
- Acid reflux/heartburn
- Dizziness (related to dehydration)
To improve tolerability, healthcare providers typically start patients on a low dose and increase it gradually.
How to Reduce Side Effects
Many side effects can be managed with simple adjustments, especially during the first few weeks of treatment. Helpful strategies include:
- Eating smaller meals
- Eating slowly and stopping when comfortably full
- Including protein with every meal
- Avoiding greasy or very rich foods
- Staying well hydrated
- Taking the medication exactly as prescribed
Maintaining an active lifestyle is essential when taking GLP-1 medications, as regular exercise, including strength training, helps preserve muscle mass during weight loss. Incorporating protein-rich foods into your meals can further support muscle health and overall well-being.
Patients should contact their healthcare provider if symptoms persist or worsen, as adjustments or dietary changes may help.
Rare but Serious Risks
Serious side effects are uncommon, but they are important to understand. Rare risks associated with GLP-1 medications include:
- Pancreatitis, or inflammation of the pancreas
- Gallstones and inflammation of the gallbladder leading to biliary colic, sometimes related to rapid weight loss
- Kidney issues, often linked to dehydration
- Thyroid tumor warnings, based on animal studies rather than confirmed human cases
These risks underscore the importance of medical supervision throughout your treatment. It’s recommended to check in with your doctor regularly, typically every few weeks or as advised, to monitor your progress and address any concerns.
Navigating Your GLP-1 Journey
Dealing with Weight Loss Plateaus
It’s normal for weight loss to slow down or stall—this is called a plateau and happens as your body adjusts to a lower weight. Plateaus don’t mean GLP-1 medications have stopped working but may require small changes.
To get back on track, consider these tips:
- Watch portion sizes and check in on your food choices
- Add more movement, especially strength training
- Prioritize good sleep and manage stress
- Connect with your healthcare provider if progress stays stalled
Long-Term Use and Maintenance
Sticking with a long-term plan is important for keeping weight off and getting the most benefit from GLP-1 medications.
- GLP-1 medications are often needed long-term for lasting weight management.
- Stopping the medication commonly leads to weight regain as appetite returns.
- Building healthy habits, such as balanced eating and regular activity, is essential.
Work with your healthcare provider to develop a long-term maintenance plan that includes both dietary and lifestyle recommendations.
Mental Health Considerations
Weight loss isn’t just physical—it can also affect your mood and emotions. GLP-1 medications may influence brain chemicals like dopamine, which help regulate reward and motivation. For some people, this can lead to changes in mood, energy, or even interest in food and activities.
It’s important to:
- Notice any persistent mood changes, such as feeling down, anxious or less interested in things you usually enjoy
- Talk to your healthcare provider if you experience new or worsening mood symptoms
- Seek support from a mental health professional for guidance and coping strategies
- Connect with others through support groups
- Check in with yourself regularly about how you’re feeling, both physically and emotionally
Caring for your mental health is just as important as physical progress and supports lasting results.
Who Should Not Take GLP-1 Medications?
GLP-1 medications are not recommended for people who:
- Have a personal or family history of medullary thyroid cancer
- Have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Are pregnant or breastfeeding
- Have a history of severe pancreatitis
A full medical history should always be reviewed by your doctor before starting therapy.
Oral (Pill) GLP-1 Medications: What’s New?
Most GLP-1 medications are given by injection, but oral options are now emerging.
- Rybelsus® is an oral form of semaglutide approved for type 2 diabetes
- Recently, the FDA approved the first oral GLP-1 medication for weight loss, expanding treatment options for patients who prefer not to use injections
Oral GLP-1 medications must be taken exactly as directed to ensure proper absorption and effectiveness.
When to Talk to a Healthcare Provider
GLP-1 medications are typically prescribed for people with:
- A BMI of 30 or higher
- A BMI of 27 or higher with weight-related health conditions
A healthcare provider can help determine whether medication is appropriate and discuss expectations, benefits and long-term planning.
Anyone considering a GLP-1 medication should begin with a conversation with a healthcare provider experienced in weight management to determine whether this approach is the right fit. To connect with experts from Stony Brook Medicine’s Bariatric and Metabolic Weight Loss Center, visit our website or call (631) 444-2274.
