What is a GLP-1 peptide?

GLP-1 (Glucagon-Like Peptide-1) is a hormone that regulates appetite, blood sugar, and metabolism. GLP-1 peptides like Semaglutide and Tirzepatide mimic this hormone to help reduce food intake and promote significant weight loss - typically 15-24% of body weight in clinical trials.

How do GLP-1 peptides work for weight loss?

GLP-1 peptides work by slowing gastric emptying, reducing appetite signals in the brain, and improving insulin sensitivity. This creates a caloric deficit by naturally reducing hunger and food intake while also improving how your body processes glucose.

What's the difference between Semaglutide, Tirzepatide, and Retatrutide?

Semaglutide (Wegovy) targets GLP-1 receptors only and produces ~15-17% weight loss. Tirzepatide (Zepbound) targets both GLP-1 and GIP receptors for ~20-22% weight loss. Retatrutide targets three receptors (GLP-1, GIP, and glucagon) and shows ~24%+ weight loss in trials.

What blood work should I get before starting a GLP-1?

Before starting GLP-1 therapy, you should get a comprehensive metabolic panel (CMP), lipid panel, HbA1c, thyroid panel (TSH, T3, T4), kidney function tests (BUN, creatinine), and baseline body composition. These help establish your starting point and screen for contraindications.

Are GLP-1 peptides safe for long-term use?

Semaglutide and Tirzepatide have FDA approval with extensive long-term safety data. Common side effects include temporary nausea, which typically resolves within 2-4 weeks. They

When will retatrutide be available?

Retatrutide is currently in Phase 3 clinical trials. Based on trial timelines, FDA approval could potentially come in late 2025 or 2026, though regulatory processes can vary. Currently, it

PeptideKey Research Library

How GLP-1 Peptides Work: The Science & Essential Blood Tests

Discover GLP-1 and incretin peptides for weight loss research. Access curated summaries, detailed safety data, and research protocols to guide your studies effectively.

This research guide is part of PeptideKey's evidence-based peptide research library covering 100+ compounds with lab-verified purity data.