GLP-1 Receptor Agonist
GLP-1 Receptor Agonist — A GLP-1 receptor agonist is a class of injectable medication that mimics glucagon-like peptide-1, a gut hormone that stimulates insulin secretion, suppresses glucagon, slows gastric emptying, and reduces appetite. GLP-1 receptor agonists are FDA-approved for type 2 diabetes and chronic weight management; major branded products include semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).
What is a GLP-1 receptor agonist?
A GLP-1 receptor agonist (GLP-1 RA) is a peptide medication that activates the glucagon-like peptide-1 (GLP-1) receptor, mimicking the action of an endogenous gut hormone released after meals. The class produces four principal physiological effects:
- Glucose-dependent insulin secretion — pancreatic beta cells release insulin in response to a meal, but only when blood glucose is elevated (low hypoglycemia risk)
- Glucagon suppression — reduces hepatic glucose output
- Delayed gastric emptying — food stays in the stomach longer, prolonging satiety
- Central appetite suppression — direct CNS effects on hypothalamic appetite centers reduce hunger and food-related preoccupation
How are GLP-1 RAs used?
The class is FDA-approved for two principal indications:
- Type 2 diabetes — to improve glycemic control
- Chronic weight management — for adults with BMI ≥30, or BMI ≥27 with weight-related comorbidities
Major FDA-approved agents in current use:
| Generic | Brands | Indication |
|---|---|---|
| Semaglutide | Ozempic, Wegovy, Rybelsus | T2D / Weight |
| Tirzepatide (GLP-1 + GIP) | Mounjaro, Zepbound | T2D / Weight |
| Liraglutide | Victoza, Saxenda | T2D / Weight |
| Dulaglutide | Trulicity | T2D |
| Exenatide | Byetta, Bydureon | T2D |
Why GLP-1 RAs matter for nutrition tracking
GLP-1 RAs typically reduce caloric intake by 20-30% via reduced hunger and earlier satiety. Common nutrition concerns include:
- Inadequate protein intake — patients often struggle to hit 1.2-1.6 g/kg protein at reduced total intake; protein-forward meal planning is essential
- Lean mass loss — without resistance training and adequate protein, GLP-1 RA-induced weight loss may be 25-40% lean mass, per Wilding et al., 2021, NEJM
- Dehydration and electrolyte loss — particularly during titration and with GI side effects
- Micronutrient gaps — sustained low intake risks deficiency
Common side effects include nausea, vomiting, diarrhea or constipation, fatigue, and (rarely) pancreatitis or gallbladder events.
This is general educational information, not medical advice. Consult your physician before starting, stopping, or modifying any GLP-1 receptor agonist therapy. Dosing, contraindications, and monitoring decisions belong to your prescriber.
See specific agent entries: semaglutide, tirzepatide, Ozempic, Mounjaro.