Also known as: Glucagon-Like Peptide-1, Incretin, GLP-1(7-36)amide, GLP-1(7-37)
Weight management and type 2 diabetes treatment via GLP-1 receptor agonism
Amount
Semaglutide: 0.25 mg escalating to 2.4 mg weekly (obesity); Tirzepatide: 2.5 mg escalating to 15 mg weekly
Frequency
Once weekly (semaglutide, tirzepatide) or once daily (liraglutide)
Duration
Chronic therapy (ongoing); weight regain common upon discontinuation
Step-wise Titration (16 weeks)
Route
SCSchedule
Once weekly (semaglutide, tirzepatide) or once daily (liraglutide)
Timing
Any time of day, with or without meals; same day each week for weekly agents
✓ Rotate injection sites
Duration
Chronic therapy (ongoing); weight regain common upon discontinuation
Repeatable
Yes
✓ Ready-to-use — no reconstitution required
Storage: Pre-filled pens: Store refrigerated at 2-8 degrees C before first use. After first use, may be stored at room temperature (up to 30 degrees C) for the product-specific in-use period (14-56 days depending on product). Do not freeze.
HbA1c and fasting glucose
When: Baseline
Why: Baseline glycemic status
Comprehensive metabolic panel (CMP)
When: Baseline
Why: Renal and hepatic function baseline
Lipid panel
When: Baseline
Why: Baseline cardiovascular risk markers
TSH
When: Baseline
Why: Thyroid function baseline (thyroid C-cell concerns in animal studies)
Lipase and amylase
When: Baseline
Why: Baseline pancreatic enzymes
HbA1c
When: 3 months
Why: Assess glycemic improvement
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Glucagon-like peptide-1 (GLP-1) is a 30-amino-acid incretin hormone produced by intestinal L-cells in response to nutrient ingestion. It plays a central role in glucose homeostasis by stimulating insulin secretion in a glucose-dependent manner, suppressing inappropriate glucagon release, slowing gastric emptying, and promoting satiety. The discovery and therapeutic exploitation of GLP-1 biology has led to one of the most important classes of drugs developed in the 21st century: the GLP-1 receptor agonists (GLP-1 RAs), which have transformed the treatment of type 2 diabetes and obesity.
The active forms of GLP-1 are GLP-1(7-36)amide and GLP-1(7-37), both cleaved from the proglucagon precursor protein. In the circulation, native GLP-1 is rapidly inactivated by the enzyme dipeptidyl peptidase-4 (DPP-4), giving it a plasma half-life of only 1-2 minutes. This rapid degradation has driven the development of DPP-4 resistant GLP-1 analogs and long-acting formulations that maintain GLP-1 receptor activation for hours, days, or even weeks.
GLP-1 exerts its effects by binding to the GLP-1 receptor (GLP-1R), a class B G protein-coupled receptor expressed on pancreatic beta cells, the gastrointestinal tract, the central nervous system, the heart, and other tissues. Key actions include:
Insulin secretion: GLP-1 potentiates glucose-stimulated insulin secretion from pancreatic beta cells. Crucially, this effect is glucose-dependent, meaning it operates only when blood glucose is elevated, greatly reducing the risk of hypoglycemia compared to insulin or sulfonylureas.
Glucagon suppression: GLP-1 suppresses inappropriate postprandial glucagon secretion from pancreatic alpha cells, reducing hepatic glucose output.
Gastric emptying: GLP-1 slows the rate of gastric emptying, reducing the rate of glucose absorption and contributing to postprandial glucose control.
Satiety and appetite reduction: GLP-1 receptors in the hypothalamus and brainstem mediate appetite suppression and promote a feeling of fullness. This effect is a major contributor to the weight loss observed with GLP-1 receptor agonists.
Beta cell preservation: In preclinical models, GLP-1 promotes beta cell proliferation and inhibits apoptosis, though the clinical relevance of these effects in humans is still being investigated.
GLP-1 was identified through the study of the "incretin effect" — the observation that oral glucose produces a greater insulin response than intravenous glucose at the same blood glucose levels. This difference is attributed to gut-derived hormones, primarily GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), which are released from intestinal cells during meal absorption and amplify the pancreatic insulin response. In type 2 diabetes, the incretin effect is substantially diminished, providing a rational basis for GLP-1-based therapies.
The rapid degradation of native GLP-1 by DPP-4 necessitated the development of resistant analogs for therapeutic use. Major approved GLP-1 receptor agonists include:
These drugs have demonstrated robust efficacy in reducing HbA1c (1-2% reductions), promoting weight loss (5-20% of body weight depending on agent and dose), and in some cases reducing cardiovascular events.
GLP-1 receptor agonists represent one of the largest therapeutic advances in endocrinology. Major clinical milestones include:
Research is expanding the potential applications of GLP-1 receptor agonists to include nonalcoholic steatohepatitis (NASH/MASH), heart failure with preserved ejection fraction, chronic kidney disease, and potentially neurodegenerative conditions including Alzheimer's disease. The breadth of GLP-1 receptor expression throughout the body suggests that its therapeutic potential extends well beyond metabolic disease.
Glucagon-like peptide 1 promotes satiety and suppresses energy intake in humans, published in Journal of Clinical Investigation (Flint A et al., 1998; PMID: 9449682):
Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes (LEADER), published in New England Journal of Medicine (Marso SP et al., 2016; PMID: 27295427):
Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1), published in New England Journal of Medicine (Wilding JPH et al., 2021; PMID: 33567185):
Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), published in New England Journal of Medicine (Jastreboff AM et al., 2022; PMID: 35658024):
We summarize new studies, safety updates, and dosing insights — delivered biweekly.
See real-world usage patterns alongside the clinical evidence above. Community-sourced, not clinically verified.
Based on 100+ community reports
View community protocolsGLP-1 (Glucagon-Like Peptide-1) is a 30-amino-acid incretin hormone produced by intestinal L-cells that stimulates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and promotes satiety. GLP-1 receptor agonists such as semaglutide and tirzepatide have transformed the treatment of type 2 diabetes and obesity.
Research suggests the following potential benefits of GLP-1: Foundation for blockbuster GLP-1 receptor agonist drug class (semaglutide, liraglutide, tirzepatide). Glucose-dependent insulin secretion reduces hypoglycemia risk. Promotes significant weight loss (up to 15-22% in clinical trials). Cardiovascular risk reduction demonstrated in major outcomes trials. Expanding therapeutic applications in NASH, heart failure, and neurodegeneration. These findings are based on available studies and the evidence level varies across different applications.
Reported side effects of GLP-1 include vomiting, diarrhea, constipation, injection site reactions. Most reported side effects are mild and transient. Comprehensive human safety data may be limited. Consult the detailed side effects profile for full information.
GLP-1 is currently in the approved stage. In the United States, it is classified as approved. Multiple GLP-1 RAs FDA-approved for type 2 diabetes (Ozempic, Victoza, Trulicity) and obesity (Wegovy, Saxenda, Zepbound) Regulations vary by country and may change.
Research protocols for GLP-1 typically use 0.25 mg to 2.0 mg weekly administered Once weekly subcutaneous for Chronic therapy. Start 0.25 mg x 4 weeks, then 0.5 mg; may increase to 1.0 mg then 2.0 mg. No standardized human dosing has been established by regulatory bodies.
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Semaglutide: FDA-approved GLP-1 agonist for weight loss and diabetes. Covers STEP/SUSTAIN trials, Ozempic vs Wegovy dosing, and cardiovascular benefits.
Liraglutide: FDA-approved GLP-1 receptor agonist for type 2 diabetes and weight management. Covers LEADER cardiovascular trial, SCALE weight loss data, and Victoza/Saxenda dosing.
Tirzepatide: FDA-approved dual GIP/GLP-1 agonist with up to 22.5% weight loss. Covers SURPASS/SURMOUNT trials, dosing, and semaglutide comparison.
Exenatide: the first GLP-1 receptor agonist ever approved, derived from Gila monster venom. Covers EXSCEL cardiovascular trial, Byetta/Bydureon dosing, and neuroprotection research.
This website is for educational and informational purposes only. The information provided is not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare professional before using any peptide or supplement.
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